Silicification Geology (OPALS) with Patrice Rey

Gems of lightning and shadows. Rainbow fossils. Underground tunnel homes. Mysterious sedimentary origins. Aboriginal dreamtime stories. Armored snails. Questionable song lyrics. It’s opals, folks. And world expert geophysicist and University of Sydney professor Dr. Patrice Rey is here to talk about why he left France to explore the geological mysteries of the Outback. Should you get an opal engagement ring? Can they get wet? What’s the difference between an Australian and Ethiopian opal? What was one doing in a Kenyan cave 3000 years ago? What’s a Kyoto Opal vs. opalite? And why was your great grandma named Opal? (Cultural warning to Aboriginal and Torres Strait Islander listeners: this episode mentions names and stories of people who have passed.)

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Alie Ward?

  Oh, hey, it's the woman at Costco testing out a hammock, Ally Ward. And this one is for October babies, anyone who has ever met an October baby too, which is all of you, because the stone of the month for October is flashy, dazzling, forever young and fragile. What are opals? Why are they so weird? What are they made of? Let's dig into it with a geoscientist and a geophysicist. And yes, world expert on opals, a professor at the University of Sydney in Australia. Hmm, Australia, ooh, we love an accent. But actually, wait, this one might surprise you. But before we get there, first, thank you to patrons who support the show at patreon.com/ologies.

• 0:44Alie Ward?

  Thanks to everyone out there in Ologies merch from ologiesmerch.com and the folks who leave reviews, which helps so much. And I read them and then I read them to you, such as this new one left from Hayansky, who wrote, "Ally is still the internet dad I never knew I needed. The optical technology episode is why I finally got my eyes checked. Turns out it wasn't just not enough sleep. I have astigmatism, lol." Kito, I'm happy to help. Also, thank you to sponsors of the show who enable us to donate to a cause of the ologists choosing each week. This episode is sponsored by Seed. Bloating, irregular bowel movement, gas. When your gut is off, it gets your attention.

• 1:25Alie Ward?

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• 2:08Alie Ward?

  You need an experienced pro who asks the right questions, sets you down a path where you're most likely to succeed. And that's what you can expect from a coach at today's sponsor, strawberry.me. This is so cool. They match you with a certified coach who's been vetted to work closely with company founders. And yeah, sometimes I'm like, oh, wait, that's right, I am one. And if you're founding a business, even if you're along the way and you're maybe stuck in a rut, or you have to make a decision about expansion, or what direction you want to take your company, that's what I did. I went to strawberry.me and I was like, okay, can you help me pare down some stuff? I think I have too much on my plate. I'm not sure what to say yes to and what to say no to. And they were super helpful in helping me streamline, and now I get to sleep more, and I enjoy that.

• 2:51Alie Ward?

  So get the help every entrepreneur needs. Go to strawberry.me/ologies. That's strawberry.me/ologies. You're the boss. Okay, so Silicification geology, it's mouthful, but you don't have to say it. You just have to listen to how the chemical compound that makes up some rock, silica, has some real main character backstory, and it transforms into fiery stone. Also, Mars? How is Mars involved? It is. So are opalized fossils, how to care for your precious gems, rockhounding, discovery sagas, the addictive nature of opal hunting, cave discoveries, Ethiopian volcanoes, moon

• 3:33Alie Ward?

  myths, childhood dreams, and Aboriginal dream stories. Also, customary warning to Aboriginal and Torres Strait Islander listeners, this episode mentions names and stories of people who have passed. So lace up the books for a jaunt to the outback, not with an opal miner, but a researcher, academic, Frenchman, opal aficionado, and Silicification geologist, Dr. Patrice Rey. He has.

• 4:18Speaker 01

  My last name is Ray.

• 4:21Alie Ward?

  And Patrice?

• 4:23Speaker 01

  Patrice, yeah.

• 4:24Alie Ward?

  Beautiful. Now, you are from France originally?

• 4:28Speaker 01

  Yes, originally from France, yes.

• 4:31Alie Ward?

  And I understand that you had some choices as to where you were gonna go study. And one of them was a cold place, and one of them was Australia. Did the opals bring you to Australia, or did the climate, or was it both?

• 4:48Speaker 01

  It was probably both. And this comes from me watching a documentary when I was around 10 years old. And it was a documentary on TV about the mining of precious opal in Cooper Pedy.

• 5:02Speaker 02

  The first thing with opal mining, of course, is to drill a shaft into the ground and find possibly opal levels, so that you know where to keep on working. This is one sort of level here. But you never know the possibilities. It could be another foot further, it could be another 10 feet further. And I think this sort of romance, or call it that if you like, keeps the people going.

• 5:28Speaker 01

  And this little documentary, you know, was my, probably the first time, you know, that Australia came on my radar. And I was really fascinated by what I saw on TV. I was looking at people digging, looking for precious gemstone. And even if they did not discover anything, they end up having these beautiful houses.

• 5:52Alie Ward?

  So when Patrice is talking about cool houses in the opal mining region of Cooper Pedy, Australia, he means cool figuratively, yes, but also literally, as these are underground dugouts that up to 60% of the town's inhabitants use as homes. So when the outside temperature gets into the 50s Celsius, or 126 degrees Fahrenheit, you too would carve a totally subterranean bunker, tens of meters underground, where it stays like a crisp wine cellar vibe year round. Some of these underground houses are modest, just practical, like a Brooklyn basement

• 6:32Alie Ward?

  apartment, while others are these internally domed palaces that you would never know lurked below the surface. And as a child on the other side of the globe, Patrice was dazzled, rightly.

• 6:48Speaker 01

  Some of them with swimming pool, underground swimming pool.

• 6:53Alie Ward?

  In Australia?

• 6:54Speaker 01

  In Australia. And I thought, okay, all right, I want mine to do that. I want mine to go to Australia and dig my backyard.

• 7:03Alie Ward?

  Okay, so just first off, Cooper Pedy, it's the name of this opal boomtown, and it comes from the Aboriginal words, "cupapiti," and that means white man in a hole. Like, people, text me on the Ouija, I'm dead. But I sent my own white ass down a rabbit hole to find this documentary. And it's stark German footage of weather-worn South Australians and immigrants from various nations tunneling into gray rock piles and sifting through dust and rubble, looking even for opal pebbles. It's this fascinating glimpse at a time mining there was still done by hand, or at best

• 7:48Alie Ward?

  cobbled together Mad Max machinery. And that's still kind of how it's done. And it also touched on the detrimental effects on Aboriginal populations who were displaced by this influx of early 1900s fortune seekers who have opal fever, as it's called. But in this documentary, Patrice also saw the underground geology in these veins of rainbow stone and a career literally immersed in rocks and their mysteries.

• 8:17Speaker 01

  So this, you know, makes a very lasting impression, to the point that when I was 14, I sent a request to the Australian Embassy about what can I do to migrate to Australia? And I do remember that I received, you know, a little package with some information. So my involvement with precious opal and my involvement with Australia started when I was 10.

• 8:44Alie Ward?

  I love that they're like, well, the first thing you have to do is turn 18, probably in order to go move to Australia.

• 8:51Speaker 01

  Exactly.

• 8:52Alie Ward?

  At 14, I'm sure your parents were like, hold on.

• 8:55Speaker 01

  Yeah, no, I was a dreamer, you know? But then you go to school, you go to uni. At uni, I studied geology, you know? Again, because I was into gemstone and volcanoes and dinosaurs, you know? So I was following this dream.

• 9:13Alie Ward?

  Patrice did a postdoc in the US and then ended up with this lectureship position at Monash University in Australia in 1995. And he wasn't working with opals yet, but he was acting out this childhood dream. He was living in Balmy, Australia, Sydney then. And at the time was working as a geoscientist on very old, very deep rocks, not relatively young surface rocks like opals. And then?

• 9:42Speaker 01

  And here I received this very strange phone call from the Lightning Ridge Opal Miner Association. That was a random call from somebody wanted to talk to a geologist interested in the formation of precious opal. And for some reason, I was volunteered, you know, to talk to that lady.

• 10:07Speaker 01

  And that was how, all of a sudden, how I reconnected with that opal story. I was really intrigued by the phone call. You know, I said to the lady, well, you know, Lightning Ridge is only a day drive from Sydney. And I'm happy to drive there and spend a couple of days with you over a weekend. And you show me around and then I will tell you, you know, what's possible to do. So this is, this is how a dream that kids can have in the back of their, their mind, materialized, you know, in some form. And to this day, I reflect a lot about that. And it's all about, once you have a dream, is sizing all the opportunities,

• 10:51Speaker 01

  you know, that will bring that dream close to you. So anyway, that's how, you know, in 2003, I started to work on precious opal. I needed to learn a lot before I could be very useful. But I could sense that the problem was solvable.

• 11:07Alie Ward?

  I understand 90% of the world's opals are in Australia, but they're scattered in maybe Idaho or Nevada. Do opals exist in France or?

• 11:17Speaker 01

  No, no, no, I don't think we have opal in France. I think there was a couple of deposits in Central Europe. New Mexico, Nevada, the vast majority of precious opal is coming from Australia. There was another type of opal in Ethiopia, but the opal there is a little bit different.

• 11:35Alie Ward?

  And these volcanic Ethiopian opals, which tend to be less expensive than the Australian ones, were discovered relatively recently by the gem industry at least, in the mid 1990s. But of course, they've been hiding in those magma-formed mountains of northeastern Africa for millions of years. But indigenous peoples in Kenya prized opals for thousands of years, as they did in Ethiopia, as specimens were discovered in 1939 alongside some 3,000-year-old cremated remains. But millennia go by and then modern Ethiopians said, hey, wow, what the heck? An opal in the village of Yedemikale in central Ethiopia. Again, just in the 1990s.

• 12:20Alie Ward?

  Well, you were in the driveway tripping on a skip it. But according to the 2020 paper, "Petogenic Origin of Mizazo Opal Hosted in Ethiopian Myocene Rhyolites", apparently now the seat of volcanic Ethiopian opal is the Wollo Province. And that wasn't discovered until 2008. I have pants older than that. And while Romans, they loved opals, so did Queen Victoria. These were mined from some small pockets in Europe. The big bump of opals happened in Australia about a decade after the 1915 discovery of surface opal by a guy named Will Hutchinson. A kid named Will Hutchinson, he was a young teenager

• 13:03Alie Ward?

  who was out prospecting for gold with his family. He was dehydrated in the desert. He was probably like, this fucking sucks. He was looking for water to survive and he found a small spring as well as a rock, just a flash with rainbow light. And there's this brass plaque memorial in the Cooper Pedy region. And it reads, "At the time, Will thought more of the water than the opal." And it continues that the Hutchinson family never profited from that opal discovery. And tragically, five years later, Will drowned while swimming in the Georgina River. So he would not live to see the opal rush that took off in the 30s.

• 13:45Alie Ward?

  And honestly, that probably prompted a lot of people to be named opal. So if you had an older aunt or something named opal, people were like, there's, there's so many opals. Everyone's talking opals. But now, third and fourth generation opal miners, they go out with buckets and shovels and from what I hear are seized by an opal fever. It's like this slot machine obsession to keep going back hours a day to find the next big cache hiding in the dust. They're all beautiful because all rocks are beautiful. But you're mentioning precious opal using that qualifier. And I'm wondering if you can describe a little bit between poach opal,

• 14:30Alie Ward?

  precious, what makes it a precious opal versus like a regular one?

• 14:35Speaker 01

  So when you look at opal in general, the vast majority of opal that can be found is poach opal. So these are the dull grayish stone that has absolutely no values. And this kind of poach opal is very common, not only in Central Australia, but in many parts of the, of the world. Precious opal is a very small percentage of opal, a few percent. And that's why they are gemstone, that's why they are precious. It's because they are much rarer. And you recognize straight away a precious opal because of its characteristic play of color. Color can be blue, green, yellow, orange, red.

• 15:21Speaker 01

  Some gemstone may have all those colors. And what is so specific to a precious opal is that no two stone looks the same. When you have seen the diamond, except for the size, they all look the same.

• 15:36Alie Ward?

  And let's bust flim flam off the bat. When we're talking about precious stones and diamonds in particular, they are, from what I understand, crystalline? They form these crystals, but opals don't? How are opals formed?

• 15:55Speaker 01

  Yeah, opal has a, has a very peculiar organization. It forms at the beginning as a gel, an unconsolidated fluid. And in that fluid, what we observe is the crystallization of silica sphere.

• 16:09Alie Ward?

  So silica, these spheres of silica are in a gel? They're kind of like in a goop in water?

• 16:17Speaker 01

  Yep, exactly. And they grow, it's not like a crystal with a nice arrangement of atoms and molecules. It is a material that starts as a gel. And, and slowly, we observe the formation of the silica sphere. In most cases, they form a kind of random arrangement. And this gives you the poach opal.

• 16:42Alie Ward?

  Okay, so yeah, most precious stones have a crystalline structure that builds on itself. But opals are weird. They form in a water-based goop and silica spheres of these different sizes glom together. If they dry over time in like a chaotic, kind of wonky way because of all these different sizes of silica spheres, you get what's called a poach opal. And it's that light gray silica-based mineraloid nobody cares about. And the miners in the documentary are sifting through that to find the flashes of colorful precious opal.

• 17:20Speaker 01

  But in some circumstances, some circumstances, those silica sphere grow and have the same diameter. And then, once you have a bunch of sphere of equal size, they will tend to have a very irregular arrangement. And it is that arrangement that explains the diffraction of the light and therefore the play of color. So it is a very unusual material in that sense. It's not a crystal. It's an amorphous material made of silica and water.

• 17:54Alie Ward?

  So yeah, an amorphous material made up of just the chemical compound of silica dioxide, which is the same stuff the sand is made of. And in crystalline form, silica dioxide becomes quartz. But in the case of opals, it's not crystalline. It's amorphous.

• 18:10Speaker 01

  So in terms of chemical composition, it's very simple. Water up to 10%, silica is all the rest.

• 18:17Alie Ward?

  So they're 10% water? Opals are 10% just, how much, how like diamonds, sapphires, rubies? Are those, do they have water in them?

• 18:28Speaker 01

  No, they don't, yeah. Opal has, has water and that's because it's probably the only gemstone I know that forms so close to the earth's surface, where water exists in abundance. So it's the only gemstone that form. You don't need high pressure. You don't need high temperature. Diamond, for instance, if you want to have a diamond, the diamond form at least at 150 kilometer depth at a temperature, you know, in excess of 1,000 degrees. But no, opal, you can make opal in your, in your kitchen. You could, you know, there is, you don't need to have fancy apparatus.

• 19:07Alie Ward?

  So diamonds, you know, diamonds, right? They form deep in the earth's crust. They form at least a hundred and fifty kilometers or a hundred miles below the earth's surface, and they need bonkers pressure and temperatures of at least a thousand degrees. And I was like, that's hot, but that's Celsius. So it's close to two thousand degrees Fahrenheit. Diamonds, they form hella deep, but then they get pushed closer to the surface over time, and diamond mines are still deep, like at their deepest, like half a kilometer down into the earth. But opal, they're pretty young, they're just chilling. They're loitering rather close to the dirt.

• 19:49Alie Ward?

  And so the shimmer is the refraction of light depending on how those silica spheres arranged as they sort of like dried out of that gel. So is that why it, does it catch the light based on the structure?

• 20:03Speaker 01

  Exactly. The color, in fact, is a function of the diameter of the sphere. The bigger the sphere, the redder they are. So in the bigger sphere, about two hundred and fifty nanometer, up to four hundred nanometer, you are in the, in the yellow, orange, red. And underneath two hundred nanometer, you are in the blue color, and the green is in between. So basically, it is the, the diameter of the sphere that dictate the dominant color. And it turns out that, of course, the red opal are the more expensive because they are the rarest. So if you find an opal which is in the yellow, orange, red, those are very high value gemstone.

• 20:46Alie Ward?

  Okay. Imagine, if you will, a ball pit at Chuck E. Cheese. Don't imagine how gross it is in there, though. But if the plastic balls are all the same size, let's say they're all like a tennis ball, and they're in a nice orderly formation stacked up, they'd be giving off a blue opal. Uh, let's say that the balls were all dodgeballs, right? From seventh grade P E. I know you remember those. They're bigger, and if they were all that size and stacked up orderly, you'd have red opal. Now, somewhere in between those sizes, let's say like the size of cantaloupe, you'd have more of a green tinged opal. And of course, if you have a bunch of different sized balls that are all, ah, freaking out in there, that's poch opal. And what about black opal?

• 21:29Speaker 01

  So black opal is a particular opal that is darker, in particular because of the presence of organic matter.

• 21:37Alie Ward?

  When you say organic material in the black opal, are we talking like old leaves or dinosaur poop? Or what kind of organic matter is in there?

• 21:46Speaker 01

  Yeah, it's the leftover of organic matter when the organic matter has been oxidized. So it's the decay.

• 21:53Alie Ward?

  Black opals are black because there is ancient oxidized, decayed stuff in them? Excuse? I love it.

• 22:03Speaker 01

  And it slowly basically turn into coal.

• 22:06Alie Ward?

  Oh, wow. It's kind of spooky.

• 22:08Speaker 01

  Yeah, yeah.

• 22:09Alie Ward?

  I feel like those are the most goth, dark, spooky decay, but precious.

• 22:14Speaker 01

  Oh, yeah. I mean, you need to imagine a landscape that correspond to a swamp.

• 22:20Alie Ward?

  Oh, cool.

• 22:22Speaker 01

  Yeah, so, and, and, and a very smelly swamp, uh, because a lot of sulfur, you know, and it's muddy and it's cold, and you have all this organic matter coming from rivers, bones and leaves and pieces of wood. And slowly this material decay, consuming oxygen.

• 22:43Alie Ward?

  Patrice says that these sought after black opals, which have been compared to the aurora borealis, they look like them, they're gorgeous. They are sometimes called gems of lightning and shadows. They emerge from areas that were once estuaries, places that were, I'll quote him, very smelly. Very smelly.

• 23:05Speaker 01

  So the precious opal start in the soup that is not very pleasant.

• 23:10Alie Ward?

  And they form this gel with these silica spheres. And if they wind up around like, you know, almost 10% water, like, is the water evaporating over millions of years or thousands of years or billions of years?

• 23:25Speaker 01

  Yeah, the transformation of the gel into something solid is probably a very slow process. A very clever opal miner managed, you know, to find the recipe to make this precious opal gel in his shed. And I had the opportunity to visit his shed, and I can confirm that, yes, that miner did find a way to form this precious opal gel. But the trouble is that he could not dry the material enough to transform the gel into something solid. And that suggests that is a very slow process where you, you extract molecule of water, you know, one at a time.

• 24:10Alie Ward?

  Wow.

• 24:11Speaker 01

  To really preserve that, that nice arrangement of, of sphere.

• 24:15Alie Ward?

  So it's like putting a birthday cake in a microwave, like it just doesn't work?

• 24:19Speaker 01

  Yeah, exactly.

• 24:20Alie Ward?

  Yeah, or is it like making a brisket low and slow?

• 24:24Speaker 01

  The formation of the gel is a fast process. It takes days, uh, but the day duration probably takes, you know, thousands of years.

• 24:32Alie Ward?

  Yeah. Could this be Pierre Gilson, a French scientist who discovered a way to make lab opals in the nineteen seventies?

• 24:40Speaker 01

  No. The Gilson is a synthetic opal that follows another process. In fact, you can buy synthetic opal, Xerox, the company Xerox that was making printers, you know?

• 24:51Alie Ward?

  Xerox? Xerox makes opals?

• 24:54Speaker 01

  Yeah, makes opals.

• 24:55Alie Ward?

  What? This is true, sort of. So Kyocera is a Japanese company, and it makes and sells printers and copy machines, and they've partnered with Xerox now. But what is Kyocera doing in the opal business? You're asking me. They're making money. They're not really making opals, though. So these, like, air quotes, stones, they are marketed hilariously, so deceptively as Kyoto opals, but they take months to make. They're indeed silica, but rather than water, they're impregnated with this polymer resin. So they can be called synthetic because they have silica in them. But let's, what am I talking about?

• 25:39Alie Ward?

  Let's get into some terms, okay? So synthetic opal, I just found this out. Synthetic opal is one that has the same properties as a natural one, the same like molecular makeup and look and feel and weight, but it's made by humans. And labs and machines can churn out what nature worked millions of years on. Now simulated opals, not synthetic, but simulated opals, on the other hand, those can be made of anything, made of plastic or iridescent glass, and sometimes passed off as real. But simulated opals, those are pure fakes. So let's say natural opals. Oh, they're like falling in love.

• 26:24Alie Ward?

  Synthetic opals? That's breeding in captivity. Now simulated opals? That's humping a mannequin. Now browse around a crystal shop, looking to change your life, and maybe you see, maybe you're me, these glowing little milky white cubes, and they're labeled moonstone or opalite. That's simulated. That's just colored glass. Did someone say opalite? Taylor Swift did on her twenty twenty five album, The Life of a Showgirl. The song Opalite, it's the single that's out, it's everywhere. I heard it in a car dealership this weekend. It features the lyrics, "You were dancing through the lightning strikes, sleepless in the onyx night, but now the sky is opalite.

• 27:09Alie Ward?

  Oh, my Lord, never made no one like you before. You had to make your own sunshine, but now the sky is opalite." Rock nerds and crystal collectors were like, girl, opalite is fake. Like, call it sea opal or moonstone, but that shit is glass sold as something precious. That's embarrassing. But Swift has since told the press that the song was inspired by her now husband's October burst stone. But she acknowledges that opalite is, quote, "actually a man-made opal." She continues, quote, "And I kind of took that metaphor of a man-made gemstone and applied it to, well, what if you make your own happiness?" End quote. Or a man makes it. Man-made happiness.

• 27:54Alie Ward?

  Okay. Either way, if you're in a lab making opalite right now, and you're listening to this, and you're like, hey, I'm not a man, I see you. Also, yes, Gilson or Kyocera or Kyoto opals are synthetic, they're made with resin. Opalite, just simulated. And if you're an onyx lover, yeah, onyx is an actual semi-precious gemstone. So it's a lapidary love story. Either way, it's rocky.

• 28:18Speaker 01

  But the thing is that you, you can tell, you know, they, they all, they look the same, they have the same pattern. It's very hard, you know, I would say, to mimic natural opal gemstone. It would be very difficult to mimic that process, you know, because of its random nature. But one thing that convinced me that I could, you know, solve that problem of the formation of precious opal is knowing that some clever miner, you know, did manage to make something very close to precious opal. He didn't want to, to share his discovery.

• 28:54Alie Ward?

  He's like, don't look at my recipe.

• 28:56Speaker 01

  Yeah, and he was a creationist, so he believed the world was made in six thousand years, and his entire purpose was to show that academics didn't know what they were talking about, you know? Yeah, he was, he was nice enough, actually, to show me his shed and, yeah, and share with me the fact that he knew at the time more than I did about the formation of precious opal.

• 29:17Alie Ward?

  I love that he was gatekeeping for God.

• 29:21Alie Ward?

  This works.

• 29:22Alie Ward?

  And if we back up a little bit, so we have silica that forms spheres. And I imagine the silica comes from decomposing rock. But how does the shallow depth and the acidity play a role in this environment?

• 29:36Speaker 01

  Yeah, so at a place where the rock meets atmosphere and water that exists at the surface. And I knew that there was nothing special about the rocks in central Australia. We are talking about sandstones. They are sandstone that derive from the erosion of volcanoes. But it's not a very particularly exceptional rock. Those rocks exist everywhere on Earth. So I was trying to look for exceptional attributes.

• 30:06Alie Ward?

  He was trying to figure out, why is Australia just lousy with opals? Why does Australia have wombats, the best accent, and a precious gem made of rainbows? Let's consult the geology. So with the 2013 publication of Patrice's paper, it was titled Opalization of the Central Australian's Great Artesian Basin: An Australian Story with a Martian Twist. This was published in the Australian Journal of Earth Sciences. And Patrice drops the bombshell that opals are the result of, quote, "an extraordinary episode of acidic weathering during the drying out of central Australian landscape."

• 30:44Alie Ward?

  He explains that a sea flooded this central Australian basin, and that acted as a sink for volcanic plastic sediments. And the sea was shallow, it was cold, it was poorly connected to the open ocean, it was muddy and stagnant. I bet it was kind of moody, but it allowed anaerobic pyrite-producing bacteria to thrive. You're like, I don't get that. We're going to explain it in a minute. But first, what inspired this research that broke geology headlines all over the world?

• 31:17Speaker 01

  The first thing that came to me was, okay, there was a lot of these rocks coming from volcanoes. And interestingly enough, volcanoes, this is a place also where precious opal have been discovered. And at the time, in fact, people thought that, oh, there was two types of opals.

• 31:34Alie Ward?

  So in fact, sedimentary and volcanic opals are not different kind of opals.

• 31:39Speaker 01

  The rock matrix from which opal form is the same.

• 31:43Alie Ward?

  So they're both sedimentary and volcanic? So it wasn't either or, they were both?

• 31:47Speaker 01

  Yeah.

• 31:48Alie Ward?

  So volcanic rock, it's a type of rock called basalt. And within basalt rock is feldspar, which is a group of minerals that contain silica. In short.

• 31:59Speaker 01

  To really decay the basalt into feldspar, the feldspar into silica, you need very acidic weathering. And this type of weathering is relatively rare on Earth. Because at the surface of the Earth, we have a lot of limestone. And limestone buffer the acidity.

• 32:20Alie Ward?

  Oh. So yes, limestone, it's a type of rock, and it's made from compressing a bunch of organic stuff, like shells and corals, into just a panini press. And into a stone of calcium carbonate. And if you want to know more on shells, I got you. We got a bio mineralogy episode, we'll link it in the show notes. But when you burn limestone, you get lime, which is really alkaline. It's used in agriculture and wastewater treatment to raise the pH and neutralize acid. So if you have limestone, there goes the acidic environment that baby opals need.

• 32:59Speaker 01

  Limestone will consume the acidity before it can weather, you know, the rest.

• 33:05Alie Ward?

  Got it.

• 33:06Speaker 01

  And this is when the pin dropped for me. I realized that there is almost no limestone in central Australia. Although it was a very shallow inland sea, there was absolutely no limestone, which is very unusual for this kind of inland sea. And the only places where you will find those very acidic weathering is typically around coal mines and any metallic mines that contain sulfur. And it is the oxidation of the sulfur that deliver these very acidic fluid. Acidic soil in estuaries, for instance, correspond to this sulfur minerals.

• 33:48Alie Ward?

  So there's the acid part of it.

• 33:50Speaker 01

  Exactly.

• 33:51Alie Ward?

  So when pyrite rusts or oxidizes, you get iron oxide and sulfuric acid. And when that volcanic basaltic rock breaks down, you get clay. And from the clay comes silica, and you also get as a byproduct, iron. Lots, lots, lots of iron.

• 34:09Speaker 01

  And this explained the red color of central Australia.

• 34:12Alie Ward?

  Oh.

• 34:13Speaker 01

  That color, red, come from that weathering.

• 34:17Alie Ward?

  And for those of me who have never witnessed central Australian topography in person, you can imagine scenes from Australia-based movies like Rabbit Proof Fence. Or The Adventures of Priscilla, Queen of the Desert, or to think of those Steve Irwin episodes, where he's out there looking for lizards or snakes. Or worst case, imagine an Outback Steakhouse in southern Utah.

• 34:44Speaker 01

  So you release iron, and then you release silica in an environment where there was no limestone. And you have this very acidic environment covering, you know, a large part of Australia.

• 34:57Alie Ward?

  When you first started studying opals, you know, a few decades ago, was this known? Or was this something that you had to put these pieces together like a detective?

• 35:09Speaker 01

  Yeah, no, exactly. It took me 10 years.

• 35:11Alie Ward?

  Patrice was being invited to symposiums and to give lectures. And they would always introduce him as the world expert on opals, which, being French, he demurred at. But the pressure of being introduced that way fueled him to be the best.

• 35:28Speaker 01

  Okay, if I was introduced that way, then, you know, I will be forced to dig a little bit and came with new information each time.

• 35:37Alie Ward?

  What pressure.

• 35:38Speaker 01

  Yeah, and surely I could, I could see, I could see all those things clicking nicely together, pieces by piece. One of the pieces, actually, that was very important was in 2008.

• 35:50Alie Ward?

  Yes.

• 35:51Speaker 01

  It was a discovery of opal and silica on Mars.

• 35:55Alie Ward?

  Yes, I was going to ask about this, being the world expert on opals, but also not only on this world, but on other planets. So yeah, what's up with Mars?

• 36:06Speaker 01

  So the discovery of opal and silica on Mars was one of these pieces of the puzzle. Because the surface of Mars is made of basaltic rock, yet again.

• 36:16Alie Ward?

  So remember, basalt is volcanic. It shoots up as magma from below the surface, and it cools fast, and it contains that silica-rich feldspar.

• 36:27Speaker 01

  And it is believed that the opal and silica was the product of this very acidic weathering. So the acid at the surface of Mars came from its atmosphere. It correspond to the time when the surface of Mars was dehydrated. So a very long, long time ago, there were free water at the surface of Mars.

• 36:52Alie Ward?

  Three billion years ago, yeah, there was tons of water on Mars' surface. Where did it go? Don't ask me. Ask Dr. Jennifer Booth, or enjoy the two-part ariology episode about Mars with her. It's fantastic. But yeah, Mars at one point was a blue planet. It was covered by giant oceans and the rivers and the lakes that you're not used to seeing. Also, up until the late 1960s, some astronomers theorized that one of Mars' moons was a hollow storage container used by aliens, like a backyard shed. This was in the late 1960s. It was like a decade after color TV came out.

• 37:35Alie Ward?

  Like, your grandparents may have already gotten fucked up on acid. And were like, I don't know, maybe it's a shed for Martians. Turns out that no, Phobos, one of the Mars moons, is just a flying pile of rubble. But the point is, we're all free balling over here, man. We just found out how opals were formed in 2012. And by we, I mean Patrice, the guy I'm talking to. But yeah, Mars, soggy place three billion years ago.

• 38:03Speaker 01

  And that water slowly disappeared. And it is at that time that the basalt were deeply weathered by this very acidic fog.

• 38:16Speaker 01

  I thought, okay, well, this is very interesting because the surface of Central Australia also went through a period of flooding and dehydration.

• 38:27Alie Ward?

  Which means the sedimentary rock oxidized, just like a rusty nail left out in the rain. And during that oxidation, sulfuric acid was released. Patrice saw this parallel between Australia and frickin' Mars.

• 38:43Speaker 01

  So I could see a parallel between the oxidation of the surface of Mars through this very acidic fog with the oxidative acidic weathering of Central Australia that allowed for the release of sulfuric acid. And by the way, we have the red center and the color is the same on Mars.

• 39:04Alie Ward?

  And by we have the red center, Patrice means like the royal we, as in Central Australia, which yes, has ruddy, iron-rich soil, just like Mars.

• 39:15Speaker 01

  The red planet and the red center.

• 39:18Alie Ward?

  Ah.

• 39:19Speaker 01

  That color is coming from that very acidic weathering.

• 39:22Alie Ward?

  Well, this was news to me just a few years ago, but opal fossils, there are fossils made of opal.

• 39:33Speaker 01

  Yes.

• 39:34Alie Ward?

  Where is this? How does it happen?

• 39:36Speaker 01

  Okay, how does it fit in the story? So that was one of the things that I needed to explain. In all opal field, you will see these precious opal filling the pore space. They are not very economically interesting because they are microscopic pores. But at the same time, you find also these opalized fossils. And it makes sense because the source of acid is the oxidation of pyrite.

• 40:02Alie Ward?

  Stay with me here, I got you. So we know we need the jelly silica from the breakdown of volcanic rock or basalt, and we also need acid, right? So where is the acid coming from in some of these places? From sulfur again? Sort of. From an iron sulfide called pyrite, also known as fool's gold. Maybe you've heard of this because yeah, it's yellow, it's shiny, it's metal, it's exciting to find on like a lakeshore until your parents tell you, no, you have not discovered treasure. You are a fool. In the eyes of science. But you know where else you can find pyrite? I'm going to tell you right now, in the shells of an endangered deep sea mollusk that lives

• 40:43Alie Ward?

  only on volcanic hydrothermal vents in the Indian Ocean. It has a regular looking snail shell. It's coiled, it's cute, we love it, but it's vulnerable, delicious, juicy, slimy foot, that's covered with overlapping metal shingles, like a knight in shimmering, pyrite, fake gold armor. Their habitat is water that's 600 degrees Fahrenheit or 300 Celsius. Its scientific name translates to golden-haired scale bearer. It's weird. Nobody told me this, you say. You know what else no one told you? That this creature, which is real, and there's some just hanging out, living their lives

• 41:24Alie Ward?

  right now, they're called the scaly-foot gastropod sea pangolin or volcano snail, made of fool's gold. How are we supposed to care about literally anything else? Let me just care about this. Let me dissociate into this volcano snail story. But Patrice explains that pyrite is a metallic product of anaerobic bacteria that munch up rotting stuff.

• 41:47Speaker 01

  It is microbes that produce this pyrite, and those microbes are in fact, the microbes that they eat the organic matter. So when you have, you know, a piece of dinosaur floating at the bottom of the sea, being buried, you know, into this smelly mud, you have those anaerobic bacteria that will use the organic matter as a source of food, and they are going to poo pyrite.

• 42:13Alie Ward?

  Metal pooping bacteria who love to eat bones. You got any rotting bones in a anaerobic, wet, muddy, oxygen-starved environment? That's fine. It remains stable as long as the moisture doesn't evaporate, which would then expose them to air and oxidize them. So, back to that muck.

• 42:33Speaker 01

  You're going to have pyrite around, and the opalization is a secondary process. So later on, when the pyrite is exposed to the oxygen coming from the surface of the earth, we release sulfuric acid and release silica, and the carbonate of the fossil will be replaced by silica. So you have molecule by molecule replacement into precious opal. And we know that because those opal fossils, they preserve very intimate detail to the cellular level.

• 43:11Alie Ward?

  Wow.

• 43:12Speaker 01

  And to achieve that, you need to have a process which is very gentle.

• 43:16Alie Ward?

  Do you ever dream about opals? Do you ever have a dream that you're looking for opals?

• 43:20Speaker 01

  Uh, no, I mean, I have, you know, foot on the ground, you know, I explore for knowledge, but I let other people doing the exploration of opal. They are beautiful character, I really enjoy. I mean, the human side of the research is something that keep me going, you know, because they are really opal miner, they are really passionate people, they are dreamers. And I do remember very early on, when I started to do research, they had a lot of expectation. I did not thought that I could crack the code, but they were telling me, you know, Patrice, you don't have to worry, even if you don't discover how precious opal is made, even if you can manage to do a few interesting things to us, this is very important.

• 44:04Speaker 01

  So they were really kind in removing pressure from my shoulder. They knew that, okay, whatever Patrice is going to do is going to be new things, we're going to learn. If it is useful for exploration, it's great. If it is not, it's still okay, you know? So they are really fantastic people and it's quite remarkable.

• 44:21Alie Ward?

  Are there any questions that you really hope to answer next? What's something that you're like, ah, I really need to find this out about opals? What's something that really gets you?

• 44:33Speaker 01

  So one of the aspects that is still open is the timing of the formation of precious opal. A lot of miners think that this is very recent, you know, 30 million years. In my research, you know, I placed the bulk of formation of opal in between 93 to 60 million years. And that's because I know for a fact that there was no fossils younger than 65 million years that have ever been opalized.

• 45:08Alie Ward?

  So yeah, how old are opals? It's anyone's guess. Well, it's literally Patrice's guess because he's the person on earth closest to finding out. And some opal miners think opals are as young as 30,000 years or even 6,000 years old, if you're a gem-loving creationist with something to prove. But Patrice thinks they're about 93 to 60 million years old because the lack of newer opalized fossils would point to that. But technology still needs to catch up to prove it.

• 45:41Speaker 01

  But there is only a few method that will allow us to date directly opal. So I probably need to wait for another 10 years that the technology evolve. The timing on when those opal form, this is an open question.

• 45:58Alie Ward?

  Oh, I love that we don't know yet. That's so exciting.

• 46:02Speaker 01

  It is, yep.

• 46:04Alie Ward?

  Can I ask you some questions from listeners?

• 46:06Speaker 01

  Sure.

• 46:07Alie Ward?

  And first, we're going to donate to a cause of this Ologies Choice, which is the gofoundation.org, which provides education scholarships for children and young people from first grade to college. And it empowers young Indigenous Australians to thrive with a focus on culture and education to help them reach their full potential. So we'll link them in the show notes, but once again, that's gofoundation.org. And thank you to sponsors of the show for making that donation possible. This podcast is brought to you by Squarespace. If you haven't heard me gushing about Squarespace for years, it's an all-in-one website platform. Whether you're trying to grow a business you have, or if you're just a baby business getting started, it has everything you need. That's where I secured my domain name.

• 46:52Alie Ward?

  It helped me build a professional site. I can update it so easily. I've been using Squarespace since before Ologies existed. After procrastinating for years, I literally built my website in one evening. They have templates, they have flexible editing tools. Squarespace also makes it easy to share your work. You can book clients, you can get paid, they have built-in tools for scheduling and invoicing and email all in one place. Whenever someone I know needs a website, whether they're a scientist that needs to put their work up, or someone who's just starting a business, I'm like, do it Squarespace. So head to squarespace.com/ologies for a free trial. And when you're ready to launch, use offer code OLOGIES to save 10% off your first purchase of a website or domain. You can do it.

• 47:37Alie Ward?

  The other day, your pod mother, Jarrett, was like, why do we have to eat every day, like three times a day? But Hungry Root, they get it, and they get to know your likes and your dislikes, your goals nutritionally, what works with your lifestyle, and then they recommend groceries and recipes just for you. They help you discover new meals, ingredients you may not have chosen for yourself, but could end up being like, this is my new favorite. Hungry Root, they just help you spend less mental energy planning meals, shopping for groceries and cooking, so you can just put that time towards what matters to you. And I teamed up with Hungry Root to create an online cookbook. It's called Pod Mom and Dad's High Protein and Low Dairy Menu.

• 48:18Alie Ward?

  And we have a protein-packed chicken avocado rice bowl, sweet potato and chipotle salad. They also have some really great veggie options too, like this Moroccan vegetable tajine, that's hecka good. You can explore my digital cookbook, Pod Mom and Dad's High Protein Low Dairy Menu, for free at hungryroot.com/ologies. And for a limited time, get 40% off your first order, plus a free item in every box for life with code OLOGIES. Ugh, trips are full of unexpected discoveries. Maybe you see a sea slug, or you find out that your friend still sleeps with a stuffed animal. But when it comes to your vacation rental, there should not be any surprises. When you book a Verbo vacation rental, if what you expect isn't what you get, Verbo

• 49:03Alie Ward?

  Care has you covered. If something's broken or just not Right. Verbo will work to make it right. Plus, you get 24/7 live human support with every booking. Grab your stuffy. We're going on vacay. So book today on the Verbo app. If you know, you Verbo. Terms apply. See verbo.com/Trust for details. Here's some things that I love to wear. Okay, I like wearing all black because it matches. Also, a sleeveless Mongolian cashmere sweater. Those are some things that I find myself reaching for all the time. And they have a permanent place in my wardrobe. And they are Quince. That's exactly what Quince does so well. They make these elevated essentials. They use premium materials and designs that are just timeless.

• 49:47Alie Ward?

  They're made to be worn again and again. They're those quality pieces that are there to stay in your closet. And as the weather gets a little more crisp, Quince, they've got everything you need to round out that wardrobe. They got warm, responsibly sourced down jackets, cozy cashmere scarves. And because they cut out the middlemen, you get very high quality stuff for a lot less money. So find the fall pieces that you will reach for most at Quince. Download the Quince app for app exclusive offers or go to quince.com. You can get free shipping on your order and 365 day returns. Now available in Canada and the UK too. And then when Quince asks where you heard about them, just let them know it was all of Jesus and Ally Ward because she loves them. It's the best way to support the show too.

• 50:33Speaker 04

  This podcast is supported by Nurtac ODT. Remajapant, we know you didn't ask for an interruption, but migraine doesn't wait for the right moment to interrupt either. It just barges in, takes your time and throws everything off. So when migraine takes your time, take Nurtac. It's for the acute treatment of migraine with or without aura in adults. Nurtac can provide pain relief in two hours, which can last up to two days. Ask your healthcare provider if Nurtac is right for you because your time is for you, not migraine. Don't take if allergic to Nurtac ODT. Allergic reactions can occur even days after use. Get help right away for trouble breathing, rash, swelling of face, mouth, tongue, or throat. High blood pressure and Raynaud's syndrome can occur. Get help for high blood pressure, numbness, coolness,

• 51:16Speaker 04

  pain, or color changes in fingers and toes. Common side effect is nausea. For full prescribing information, call 1-833-4-NUR-TAC or visit nurtec.com. All right, back to your podcast playlist or whatever's keeping you going today.

• 51:33Alie Ward?

  Okay, we are back. We have a stack of your questions, patrons. And if you're envious of this, you can sign up yourself at patreon.com/ologies to submit yours before we record. And we also have like a weekly discussion thread about the episodes. It's just kind of a nice place to kick it with other listeners such as. I thought this was a great one. Comet Omelet wanted to know, what would it take for me to opalize my skeleton? Would it take a million years?

• 51:58Speaker 01

  Okay, all right. That's an interesting question. If you want to opalize your skeleton, okay. Well, that's going to be, that's going to be difficult. That's going to be hard. So you need a source of facility, but at the same time, you need this silica. You need to, I will put, you know, your skeleton into a silica gel. And I will make sure that I am within the pH window that allow this very slow dissolution of the bones and the replacement with silica molecules.

• 52:34Alie Ward?

  So dump your bod in a vat of amorphous silica goop. Check the pH to make sure it's acidic and low as hell. And then just enjoy the ride. Also, I like that Comet Omelet did not ask this of Patrice directly, yet Patrice answered it in the first person, just immersed in the problem to find a solution.

• 52:55Speaker 01

  So probably will take, you know, hundreds, if not thousands of years to achieve that opalization.

• 53:04Alie Ward?

  But it's possible. I mean, when you're dead, you're dead. So there's no hurry.

• 53:08Speaker 01

  Yeah, of course. And then you.

• 53:10Alie Ward?

  You're not going to get more dead.

• 53:12Speaker 01

  No, you're right. Yeah, and you have plenty of time, so.

• 53:15Alie Ward?

  Plenty of time. Well, Marla J. and Addie Capello wanted to know, in Marla's words, do opals look different when they're polished? Or do they look like these precious jewelry grade opals right from the ground?

• 53:29Speaker 01

  Right from the ground.

• 53:31Alie Ward?

  Wow.

• 53:32Speaker 01

  They're just as beautiful. I mean, to me, I like a precious opal when it is still within its rock matrix. I really love, and of course, there was a bit of polishing being done. But to me, when I can see the veins, you know, this is how opal looks the best. But no, when you extract the opal from the rock straight away, you know that this is precious opal.

• 53:55Alie Ward?

  Oh. Dr. Lena Carpenter and the other Maya, Maya's words, wanted to know, is this a thing I could go out and rock hunt or no? Like, is this a little nuggy? Or do you need to open up the earth and find a vein? Maya asked. How are you finding it? And what is that like? Do you have to shine a UV light to find it? Or are you just out there with sunscreen and a bottle of water kind of walking around? Is that, is that just a bonkers feeling to find it?

• 54:21Speaker 01

  So opal miners, over the years, they are figuring out where they should look on the landscape. So they are masters of chasing patterns.

• 54:32Speaker 01

  It's a very narrow bend of rock. And quite often, my advice to opal miners is, okay, chase those platforms and try to dig through the silcrete, which is maybe a meter or a couple of meters in thickness. And there was plenty of places in central Australia that have never been explored. Interestingly enough, where opal exists can be right there at the ground surface. And some opal miners have told me that you can find precious opal right there on the ground surface. You don't need to dig.

• 55:08Alie Ward?

  Yeah, so they are very surface, can be.

• 55:11Speaker 01

  Yes, yeah.

• 55:12Alie Ward?

  Other times, they might be right under a cap of that poach opal or the grayish rock, just a few feet deep, hiding from you.

• 55:21Speaker 01

  If you know to read the landscape, then you have a good chance actually to find precious opal.

• 55:27Alie Ward?

  Well, Corey wanted to know, I remember hearing somewhere that opal veins can regenerate in decades. Reality or flim flam? Is that real?

• 55:38Speaker 01

  Again, the precious opalized gel, this can form in days.

• 55:45Alie Ward?

  Oh, yeah, wow. In days? If you mix the silica based basalt with sulfuric acid.

• 55:52Speaker 01

  You will see the pH changing very fast, in a matter of hours. So this reaction is very fast and can release this very precious gel in a matter of days, transforming the gel into a solid rock, something that you can cut and polish or make a jewelry out of. This process of dehydration is the one that, I don't think the one has mastered already.

• 56:21Alie Ward?

  But it would take so many years for it to dehydrate once it forms that gel.

• 56:27Speaker 01

  Exactly.

• 56:28Alie Ward?

  You need to be patient.

• 56:30Speaker 01

  You need to be patient, yeah.

• 56:32Alie Ward?

  You mentioned the process of mining and that you work with them. Empress of Smallwood, Kelly Shaver, Momo, Yuri, Laura McLean, the other Maya, RH Puff and Stuff, Dee Dee Noodle, wanted to know, in the Empress of Smallwood's words, how does the process of mining opals compare to mining of diamonds? Are there similar ethical concerns? And yeah, Kelly Shaver asked if there are ethical or environmental considerations for opals, like with other gems and minerals.

• 56:58Speaker 01

  I mean, the process of mining opal versus mining diamond is vastly different. It requires a lot of capital to open a diamond mine. You need to dig deep and you need to remove a lot of material to find those tiny diamonds. So it is a very labor intensive. You need huge capitals. And that's very different in opal mining. Basically, it's a small group of people, usually two, three, working together to do the exploration, the digging. Usually you use a shovel and a pick. If you are lucky enough to find opal,

• 57:42Speaker 01

  you can get an excavator. And then you have people specialized into the polishing of those rocks. It's a very cottage industry. In terms of environmental footprint, those mines are very small, individual mines. You know, they sit on a piece of land, which is typically 50 meters by 50 meters. And yes, you cannot mine without environmental impact. And there is strong regulation, you know, in particular in Queensland, where you have the responsibility to clean up the mining sites. And actually, this is one of the reasons why the industry is dying is because of this important regulation

• 58:24Speaker 01

  that makes the opal mining a growingly expensive activity. And when you add the cost of diesel and insurance, you know, you realize in fact it's getting more and more difficult to go into opal mining.

• 58:41Alie Ward?

  Are they scarce enough to keep up with demand too? Or are we seeing a scarcity of them?

• 58:49Speaker 01

  Because it is a cottage industry, you will very rarely see ads on magazines, you know, to encourage people to buy precious opal. But there is still plenty of precious opal to mine in central Australia.

• 59:04Alie Ward?

  Plenty, of course.

• 59:05Alie Ward?

  Like enough until it's not. And rarity is what makes gems valuable. And because they take perhaps at least 65 million years to form, they're not a renewable resource per se. Opals were only discovered in Australia in 1915, remember, and in Ethiopia in the 1990s. So we hit the ground running here. Will we exhaust them before we're extinct as a species? Well, in 2026, it's looking like a no. But still, Yudi, Aussie gardener Gabby from Brisbane.

• 59:38Speaker 05

  It is not pronounced Brisbane, but Brisbane.

• 59:42Alie Ward?

  Sorry. And Atlas would love to hear about the ethics of opal mining, especially with respect to indigenous rights in the region and the environmental impacts.

• 59:52Alie Ward?

  You know, with regulation and making sure everything's above board, Atlas wanted to know about the respect to indigenous rights in the region.

• 1:00:01Speaker 01

  So different states will have different rules. In New South Wales, opal mining is only authorized in particular places. And there was, of course, negotiation with native people. In other places, you know, like Queensland, but most of the time, there was strong regulation in where you can open a mining list. And those regulations always involve Aboriginal people, landowner. In fact, a few years ago, I was in Winton in Opal Town and I meet a couple of Aboriginal owners there. And they were working, actually, with opal miners to figure out where they could and where they could not mine. And because those are really small communities,

• 1:00:46Speaker 01

  there is a strong understanding of native rights.

• 1:00:50Alie Ward?

  And these native title agreements, as they're called, have been in flux over the years with these small mining operations, usually 50 by 50 meter plots, typically mined by one person or a family, permitted under the agreement that the indigenous people of the region have some say over the land. And according to the site for First Peoples of Australia Relations, the native title honors the laws and customs observed by Aboriginal and Torres Strait Islander people when Australia was colonized by Europeans. And it says that for the native title to be recognized, those laws and customs have to be acknowledged and observed in a substantially uninterrupted way. And from a legal standpoint, a native title is recognized

• 1:01:35Alie Ward?

  through a determination made by the Federal Court of Australia. And it's going to vary for each group because it derives from the traditional laws and customs of the local group. And it can be extinguished because of certain actions that are inconsistent with native title law that the government may have taken or allowed others to take over a particular area of land. And as Aboriginal people have had a relationship with opals for 60,000 years, the gem does appear in many of their traditional narratives, of course. And those are called dream time stories. And Megan Becken, Yudi, and Megan Walsh Gerard asked about the indigenous folklore of opals.

• 1:02:19Alie Ward?

  And there are beautiful tales, like native groups which feel like the creator appeared as a rainbow and made the opals and turned it into the fire of the earth. There are stories of ancestors' spirits carried in the opals and the minerals. But the late Yorta Yorta elder and poet Auntie June Bark, who has been described as a fierce advocate for Aboriginal rights, told this dream time story of Palapala, who was a beautiful butterfly with rainbow colored wings, who explored too far up a mountaintop and was covered by the white snow, washing all of her colors and leaving her this drab colored moth.

• 1:03:01Alie Ward?

  And her colors ran into the ground and became the lightning ridge field of opals. And it's also important to note that, again, Aboriginal peoples have known of Australia opals for tens of thousands of years. And some say that they didn't mine or collect them because opals simply belonged to the earth. And what is of value truly is food, water, safety, and companionship. Other Aboriginal peoples have made their independent living off of opal mining. But either way, it's okay to enjoy a rock and keep walking. But of course, if it means a lot to you.

• 1:03:40Alie Ward?

  Well, we had a few people who have opal engagement rings. Becky the Sassy Seagrass Scientist, Carrie Steele, Lizzie Carr. Becky says they wanted an engagement ring that was an opal, but their husband wanted something that was a harder stone. And she wanted to know, is he full of shit or not? Or do you need a, for an engagement ring for daily wear, should you get something harder? And a lot of people wanted to know where it falls on the Mohs scale and how to care for it well.

• 1:04:07Speaker 01

  Yeah, you need to look after the stone. It is strong enough, you know, to be, you can wear an opal every day. But, you know, it doesn't have the strength of diamonds, for instance. So if you have a really good quality stone, a hard stone, and it will be resistant to scratch. And if the stone fall on the ground, it will not break. However, if you have a poor quality stone, it can crack and it can scratch, you know, depending on some circumstances, you can, you can scratch it. But the interesting thing, you can polish it as well. So I will not be worried too much about scratch because you can always polish it back to something really smooth and, and perfect. But yeah, some poor quality stone can crack.

• 1:04:52Speaker 01

  And that's, again, linked to the presence of water. Sometime, there is still a little bit of water in the pore space of opal. And some opals are more porous than others. And I suspect that it is that pore space that can make the stone a bit weaker. So yeah, you need to be a bit careful. But if you have a good quality opal, it is still a very solid gemstone.

• 1:05:16Alie Ward?

  And so some are more solid. But before you try scratching glass with yours to test it out, it's about as solid as glass. But know that on the gold standard of the Mohs scale, where they decide how strong a gem is. If diamonds, they're the hardest of gems, right? They're a 10. Rubies and sapphires being the next tough. Opals are a five or six. The Gemological Institute of America, they do not mince words. They stated on their website that opals, quote, toughness is very poor to fair, making opal a gem that is suitable for jewelry, but requires care when wearing.

• 1:05:57Alie Ward?

  And apparently, pendants tend to have kind of cushier lives than a ring. A ring is swinging into all kinds of stuff, getting washed 15 times a day. I hope, I hope you're washing your hands. But hey, opals, you're not as soft as a pearl, which is an oyster dingleberry that can take like six months to form as opposed to your 75 million years. So given this, how do we care for our fragile, delicate rainbow rocks? The opals, asked Anna Rose, Jackie G, Lottie, and gardener Gabby. Okay, so the Gemological Institute says if it gets dirty, don't dare bust out the ultrasonic jewelry, or in my case, Invisalign retainer slash jewelry cleaner, unless you want it to crack, buddy.

• 1:06:42Alie Ward?

  The only safe way to clean an opal is with warm, soapy water. On the topic of warmth, by the way, Amy Arugula asked, I've heard not to wear my opal jewelry in the winter because it could crack in the cold. Is that really a concern? Why might that happen? And again, the GIA says that sudden temperature changes because of the water in the stone can cause it to fracture. So being outside in the freezing cold and then going and hopping in front of a toasty stove, it's more comfortable for you than your opal. Likewise, if you sit in the Australian sun, the heat from that could make your opal crazy. And by that, I mean it can cause crazing, which are fractures. What if you take a dip in the lake? Are opals gremlins?

• 1:07:25Alie Ward?

  Greg Wallach asks, can opals get wet or no? I've heard that water can steal their fire. And this was echoed by patrons Lydia Meyer, Emma Ruoff, and Jess Baugr. And Australian opal experts say, no, water's fine. Australian opals, they're non-hydrophane, meaning that they don't take up more water. Ethiopian opals, however, are hydrophane. They tend to be thirstier and more porous, and they can soak up water. So if they yellow, the Ethiopian opals, when wet, you have to let them slowly dry. Don't blast them with a hairdryer, and they should pop back to life. Now, it's the doublet and triplet opals, which are actually just veneers of opals glued on to another background. Those can't get wet because the layers are going to separate.

• 1:08:10Alie Ward?

  That said, leaving opals in general in low humidity for a really long time isn't good for them. Now, Chickenhawk asked, is it true that opals should be stored in a moist environment, either wrapped in damp cotton wool or a little dab of petroleum jelly? And no, if it's an Australian opal and it's non-hydrophane, that won't do anything except give you a slippery opal. And if they're Ethiopian or hydrophane thirsty opals, they will soak up a little bit of water, but they'll soak up oil or lotion or sunscreen or body oils or even dust. And that can interfere with the play of light, turning them yellow, perhaps permanently.

• 1:08:51Alie Ward?

  And then you're really shit out of luck unless a jeweler can buff that out. But Erin Armitage, who asked, is there any way to revive an opal that is dulled from body oil, lotion, et cetera? You gotta buff it out or you got to go back in time and not get them oily in the first place. Alexandra Ross said, my dad was a gem dealer on the side during the 1960s to 80s. I bet he had some facial hair that was hot as hell. But sometimes, Alexandra continues, if he felt an opal was looking dry, he would soak it in glycerin for a month or so. Was that of any use whatsoever? Or just some weird idea he picked up? Alexandra, the answer is sort of. He may have had some pre-internet information

• 1:09:35Alie Ward?

  that was handed down from other jewelers. Because usually, when an Australian opal is cracked, you can mask the crack with water or oil. But when it dries out a little, the cracks become visible again. So as a gem dealer, it's a good way to spruce one up for sale. And then they buy it and then they go, oh, man, it's cracked. But the TL, DL on that is that opals need different things depending on their origin. Please know what that is and be nice to them.

• 1:10:04Speaker 01

  And again, you know, let's not forget that those rocks, they existed a few meters underground sometime, you know, right at the surface. They have endured very significant temperature variation, water levels, and they have been here for tens of million of years.

• 1:10:22Alie Ward?

  What's the most beautiful one you've ever seen?

• 1:10:25Speaker 01

  Oh, okay. So the most beautiful one I've seen was in a place close to Quilpi, which is south of Queensland. It was a piece about, I would say, forty centimeters by thirty centimeters in thickness, about ten, fifteen centimeters.

• 1:10:43Alie Ward?

  So this is a slab of opal, imagine, about a foot square and five inches thick. Picture three loaves of Wonder Bread in a row, but an opal, a real unit.

• 1:10:55Speaker 01

  And basically, that slab was looking like a landscape.

• 1:10:58Alie Ward?

  Oh.

• 1:10:59Speaker 01

  And it was, I mean, there was one of the most spectacular opal I ever seen. So it's not something that you wear, that's for sure. But as a, as a piece of opalized rock, that's definitely the, the most beautiful sample I ever, I ever seen. And then I've seen a lot of beautiful pieces through my years. None of them I could afford.

• 1:11:25Alie Ward?

  Oh, yeah.

• 1:11:27Speaker 06

  That's cute. I wish I could get it.

• 1:11:30Alie Ward?

  What do you love the most about your job or your research or about opals in general? Or no, actually, no, don't answer that yet. I meant to ask, what's the hardest part first? Is it bugs when you're out on site? Is it emails? Is it like, what is something that is?

• 1:11:48Speaker 01

  Oh, the thing annoying is all the thing that, is all the thing that prevent you to go in the field. And also to me would be, all right, all the paperwork I need to do to show that I'm safe. Because, yeah, you, you go underground, you know, this underground mine. Sometime the, the safety is, is not a very strong consideration.

• 1:12:15Speaker 01

  So I need to convince my boss at Sydney Uni that I'm, I'm, I'm safe. And this require filling many papers, doing a lot of justification, doing a lot of admin. So this is, this is the thing that, that I find difficult. But no, once I am in the field, it's very easy. I, I will go always with the miners with me. And they are always keen, you know, to bring me underground and show me the mine and the, the mining operation and talk with me about the mining process and the exploration process. That's the easy bit. Yeah. The bit before is all the admin that we are required to do to make sure that we do our field work safely, which is painful, but which is also necessary.

• 1:12:59Alie Ward?

  And you don't get claustrophobic?

• 1:13:03Speaker 01

  Uh, a little bit. I have, I have to say that I, I've done things, you know, underground that, yeah, I was a little bit nervous, you know, when you have to squeeze your body, you know, into very small opening and you don't know what is on the other side. That's the kind of thing that I, I do not like.

• 1:13:23Alie Ward?

  Yeah. I totally understand. It's like for the love of the game. What about, what is something that you just love about it so much?

• 1:13:34Speaker 01

  Well, to me, the thing I really love about opal is that we are touching something that was there, you know, at the very beginning of the white presence in Australia. I have the feeling that I am in touch with those very early days. And you are with dreamers. It's kind of, you know, very beautiful. I love that I'm touching a bit of, of Australian history. And in fact, I remember one of my motivation came from my embarrassment to learn that, you know, opal is our national gemstone.

• 1:14:11Alie Ward?

  Yeah.

• 1:14:11Speaker 01

  You know, in nineteen ninety-three, Australia decided that, okay, we need a national gemstone and opal is our gemstone. I, I felt really, you know, compelled to do something. Well, I decided that I may as well give a crack. One way to do it was to really engage with research and try to really understand how our national gemstone did form.

• 1:14:33Alie Ward?

  I love that it took a guy from France.

• 1:14:36Speaker 01

  Yes. And it, it took a little boy, you know, watching TV and, and dreaming about, you know, becoming an opal miner.

• 1:14:43Alie Ward?

  Oh, did you ever get to live in a cool house?

• 1:14:47Speaker 01

  Uh, not as cool as the one in Coober Pedy, but it is cool. Yeah. I have a nice backyard and a swimming pool. It is not underground, though.

• 1:14:56Alie Ward?

  Your younger self would be so excited that you get to do what you do.

• 1:14:59Speaker 01

  And it was a pleasure. Thank you for, for, for reaching out.

• 1:15:03Alie Ward?

  So ask smart people, not smart questions, like how old are opals? Because honestly, they don't even know, which is thrilling. Thank you so much, Patrice, for being on the show and chatting Rainbow Rocks with me. And everybody out there, say hello to your opals, learn about them, take good care of those babies. Some people say that if someone gives you an opal as a gift, you have to give them a penny because that is better luck. That's also true with knives, but also luck is really in the eye of the beholder. And I behold opals to be gorgeous. Okay. So there are links in the show notes to our website with much more information as well as to gofoundation.org. There are links to Smologies' kid-friendly episodes, Ologies merch, patreon.com/ologies

• 1:15:47Alie Ward?

  to submit questions before we record. You'll also find our social media, which is at Ologies on Blue Sky and Instagram. And I'm at Ally Ward on both. Erin Talbert admin Seologies Podcast Facebook group. Kelly Ardwire makes the website. Aveline Malik does our professional human-made transcripts. Backdating us is scheduling producer Noel Dilworth, managing director Susan Hale, keeps our ball pit in formation. And the overlapping scales on my slimy feet are dual editors, Jake Chaffee and lead editor Mercedes Maitland of Maitland Audio. Special thanks to Australian Patrice for giving me a heads up on opal fever and for your delightful accent. I wish I could impersonate it, but gnar, I can't.

• 1:16:30Alie Ward?

  Nick Thorburn glittered out the theme music. And if you stick around to the end of the episode, I tell you a secret. And this week is that on Saturday, September twenty-sixth, Los Angeles, where I live, had a sunset that was probably the best in the last several years. Just this wide open sky, burning orange and pinks, this horizon of fire and light, the kind of sunset that you only see airbrushed on vans from the nineteen seventies or on bottles of suntan lotion, which honestly pale in comparison. My social media algorithm,

• 1:17:10Alie Ward?

  it was like the Dodgers won the World Series. It was just all vistas from Southern California, mountain tops, from the beaches with the silhouettes of palm trees, even from like the parking lot of a Del Taco. It, it was this, this sunset was the site that buoyed our collective spirits. I did not know what happened at all until the next day when I saw it on social media because I was at a car dealership filling out paperwork and learning about engine warranties and waiting for some guy's boss to be off the phone so that we could pretend to haggle on a vehicle for Jared that has working airbags and a steering wheel that doesn't randomly lock up on the freeway. An upgrade indeed.

• 1:17:54Alie Ward?

  But touche, Los Angeles. Your sunsets, your hot breezes, but you are also car negotiations on a Saturday night. But the beauty of the sunset, we'll get one tomorrow. You never know. It's like opals. You just stay addicted because they're so beautiful. So keep it on the sky or scan the ground for rainbows. All right. Bye bye. Pachydermatology, omeology, cryptozoology, lithology, nanotechnology, meteorology, geology, geology, geology, seriology, geology.

• 1:18:37Speaker 06

  Well, Opal, thank you for letting me know. I, I assure you, I had no idea.

• 1:18:41Speaker 07

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• 1:19:11Speaker 04

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