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The Rock-Forming Minerals. Geology 101: Minerals Part 3 · PlanetGeo: The Geology Podcast

• 0:01
  SPEAKER_00: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:14
  SPEAKER_00: Hey folks, this is part three of our Camp Geo Intro to Minerals series.
• 0:19
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• 0:22
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• 0:28
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• 0:33
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• 0:35
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• 0:36
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• 0:48
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• 0:50
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• 0:51
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• 0:55
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• 1:01
  SPEAKER_00: Hi Professor Professor Remick.
• 1:04
  SPEAKER_00: Hi, Chris.
• 1:04
  SPEAKER_00: How are you doing?
• 1:05
  SPEAKER_00: Are you ready for class today?
• 1:08
  SPEAKER_00: Sit there, be quiet, and listen to me, will you?
• 1:13
  SPEAKER_00: How's my overeducated little friend doing today?
• 1:16
  SPEAKER_00: Uh yeah, hanging in there.
• 1:17
  SPEAKER_00: This is great.
• 1:17
  SPEAKER_00: This is really fun.
• 1:18
  SPEAKER_00: All right.
• 1:19
  SPEAKER_00: We're on the third episode here.
• 1:21
  SPEAKER_00: We're in minerals.
• 1:22
  SPEAKER_00: We're in the minerals chapter, starting out with our intro to physical geology.
• 1:26
  SPEAKER_01: Today's episode is called Other Mineral Groups and the Rock Forming Minerals.
• 1:32
  SPEAKER_01: But before we get into that, let's talk a little bit about what we did last episode.
• 1:37
  SPEAKER_01: In our last episode, we talked about the different layers of the earth based on chemical composition, crust, mantle, and core.
• 1:44
  SPEAKER_01: So we talked about the atoms that are present and abundant in each of those layers.
• 1:49
  SPEAKER_01: And we ended with the crust and the abundance of silicon and oxygen in the crust and why that's important.
• 1:56
  SPEAKER_01: And what that led to is silicon and oxygen forms a pyramid-shaped, what we call tetrahedron.
• 2:04
  SPEAKER_01: And there are five different silicate structures that we discussed last episode.
• 2:09
  SPEAKER_01: There was the single tetrahedron, the single chain, double chain, sheet silicate, and then finally the most complicated framework silicates.
• 2:18
  SPEAKER_00: Yeah.
• 2:18
  SPEAKER_01: Where are we going today?
• 2:20
  SPEAKER_00: Yeah, so that was a really good overview of the silicates that we had did last episode.
• 2:24
  SPEAKER_00: Now we're going to get into some other mineral groups.
• 2:27
  SPEAKER_00: We're going to briefly touch on different mineral groups other than silicate structures.
• 2:32
  SPEAKER_00: We're going to talk about where minerals form briefly, and we're going to talk about the rock-forming minerals, a category of minerals that are so common that they are prevalent in most rocks.
• 2:41
  SPEAKER_00: So if you know these minerals, this suite of 10 minerals, you can identify most minerals that are common in many rocks.
• 2:48
  SPEAKER_00: There are a lot more minerals.
• 2:49
  SPEAKER_00: There's about 7,000 minerals out there.
• 2:51
  SPEAKER_00: These 10 are the most important.
• 2:53
  SPEAKER_00: So we're going to focus on those.
• 2:54
  SPEAKER_00: And the images we have in the stack right now, there's a lot of images.
• 2:57
  SPEAKER_00: That's because we have an image for each mineral that we're going to talk about.
• 3:00
  SPEAKER_00: Yes.
• 3:00
  SPEAKER_00: Okay, Chris.
• 3:01
  SPEAKER_00: So we talked about the silicates a lot.
• 3:03
  SPEAKER_00: What are the other, what are a few at least of the other major mineral groups?
• 3:08
  SPEAKER_01: Well, it's based upon something that we defined back in episode one, what an anion is, this negatively charged ion.
• 3:15
  SPEAKER_01: Okay.
• 3:16
  SPEAKER_01: And with the silicate structures, the SiO4, that forms a negatively charged ion.
• 3:21
  SPEAKER_01: So the SiO4 is the dominant anion, and that's why we call it a silicate.
• 3:27
  SPEAKER_01: Okay.
• 3:28
  SPEAKER_01: So these other mineral groups are also based upon that principle.
• 3:32
  SPEAKER_01: What's the dominant anion present?
• 3:35
  SPEAKER_01: And there we, you know, we're going to list a few of these, and there's an image that gives a list of the different mineral groups.
• 3:42
  SPEAKER_01: Okay.
• 3:43
  SPEAKER_01: It's the first image in your stack today.
• 3:45
  SPEAKER_01: And so we're going to give a list, but it's not a complete list.
• 3:48
  SPEAKER_01: I mean, we could go, we could kind of get into the weeds on this, but we're not going to do that.
• 3:51
  SPEAKER_01: We're just a couple examples and some important ones too.
• 3:54
  SPEAKER_01: So the first one is called the carbonates.
• 3:58
  SPEAKER_01: Okay.
• 3:58
  SPEAKER_01: And the dominant anion in the carbonate is CO32 negative.
• 4:04
  SPEAKER_01: Okay.
• 4:05
  SPEAKER_01: So it's got carbon, three oxygen atoms, and it forms a two-negative charge.
• 4:10
  SPEAKER_00: I just want to add one thing here.
• 4:12
  SPEAKER_00: An anion, as we talked about it early on, was a single atom that had a negative charge.
• 4:16
  SPEAKER_00: Now we're talking about molecules that are have a negative charge.
• 4:21
  SPEAKER_00: So we can talk about anions both with a single atom and with a molecule, atoms bonded together.
• 4:26
  SPEAKER_00: So we're talking about both the silica tetrahedrons and the these mineral groups based on carbonate.
• 4:32
  SPEAKER_00: That is an anion that is a molecule.
• 4:34
  SPEAKER_00: So I just want to clarify that here.
• 4:35
  SPEAKER_01: Yeah, that's a really good point.
• 4:37
  SPEAKER_01: Um, thanks for doing that.
• 4:38
  SPEAKER_01: So, Jesse, go ahead.
• 4:39
  SPEAKER_01: What are the other two mineral groups that we're gonna actually?
• 4:42
  SPEAKER_01: You know what?
• 4:43
  SPEAKER_01: Let me uh go back.
• 4:44
  SPEAKER_01: So the carbonates, this is a really important mineral group, actually, because the carbonates, the most common carbonate is a mineral called calcite.
• 4:54
  SPEAKER_01: And it's a very common mineral, first of all.
• 4:57
  SPEAKER_01: It's a very common mineral in a very important rock, too.
• 5:01
  SPEAKER_01: And so this is easily, I think, the second most important mineral group behind the silicates.
• 5:08
  SPEAKER_00: That's exactly right.
• 5:09
  SPEAKER_00: And the other one, the other two are sulfates, which is based on the SiO4 anion, which has a two-minus charge, and phosphates, which are based on phosphorus, PO4, three-minus charge.
• 5:21
  SPEAKER_00: And those are anion groups that we can put cations with to make different minerals, and those mineral groups will be the sulfate group of minerals or phosphate group of minerals.
• 5:29
  SPEAKER_01: Not to put you on the spot, Jesse, but do you have a common example that a lot of people, a lot of our listeners might know of a sulfate or a phosphate?
• 5:41
  SPEAKER_00: Yeah, one common sulfate, and especially growing up in Michigan, is gypsum.
• 5:45
  SPEAKER_00: Gypsum is a sulfate mineral.
• 5:46
  SPEAKER_00: It has uh based on the sulfate group, and it's common, it's mined as a salt in many places.
• 5:52
  SPEAKER_00: And so that's one common phosphate, another uh very common phosphate is apatite, which is calcium phosphate, which is basically the composition of your teeth, but it also occurs naturally as a mineral.
• 6:03
  SPEAKER_00: And so gypsum is a very common sulfate group mineral.
• 6:07
  SPEAKER_00: Probably the most common phosphate group mineral is what's called appetite.
• 6:11
  SPEAKER_00: And appetite is calcium phosphate, it's actually the mineral that makes up our teeth, but it's found naturally in the environment as well.
• 6:16
  SPEAKER_00: And actually, apatite is one of the minerals that we do a lot of analysis of in my research lab.
• 6:22
  SPEAKER_00: We can now determine the age at which appetite grew.
• 6:25
  SPEAKER_00: So whether appetite is growing in sediments or growing in igneous rocks, we can date that pretty accurately.
• 6:31
  SPEAKER_01: I'm I'm pleasantly surprised, Jesse.
• 6:34
  SPEAKER_00: You pulled that through nice.
• 6:35
  SPEAKER_00: You know, Chris, I had this one geology teacher in high school who was actually a really good teacher.
• 6:39
  SPEAKER_00: I don't know, uh, you know, he teaches at Hotsufo, but he taught me all these things.
• 6:43
  SPEAKER_00: How good's that?
• 6:44
  SPEAKER_01: Wow.
• 6:45
  SPEAKER_01: That's you know, that must be a good person.
• 6:47
  SPEAKER_01: Yeah, yeah, right there.
• 6:49
  SPEAKER_00: Real decent guy.
• 6:50
  SPEAKER_00: Okay, so let's move on, Chris.
• 6:51
  SPEAKER_00: Let's go into the environments in which these minerals grow.
• 6:55
  SPEAKER_00: We're gonna cover these now, but they'll be really important throughout the entire length of this class, these mineral forming environments.
• 7:02
  SPEAKER_01: Yeah, I think so.
• 7:03
  SPEAKER_01: This is uh just something that I it gets at like a basic geology thing.
• 7:07
  SPEAKER_01: Where do minerals grow?
• 7:09
  SPEAKER_01: And I, you know, we've we've talked about this.
• 7:11
  SPEAKER_01: I think you can narrow it down to four environments in which minerals will form in.
• 7:16
  SPEAKER_01: Okay.
• 7:17
  SPEAKER_01: The first of the four is what's called an igneous environment.
• 7:20
  SPEAKER_01: And it's just like to me, I think the word is intuitive igneous to ignite.
• 7:25
  SPEAKER_01: Okay, so these are minerals that will grow out of cooling molten rock.
• 7:31
  SPEAKER_01: So it's either going to be magma or lava.
• 7:34
  SPEAKER_01: And as the as that molten rock cools off, the elements and molecules will move closer together and form chemical bonds.
• 7:42
  SPEAKER_01: And so that's a really common environment in which minerals grow.
• 7:45
  SPEAKER_00: Yeah, igneous rocks.
• 7:47
  SPEAKER_00: That's kind of the focus of a lot of my research is on igneous rocks, so I won't belabor that point too much.
• 7:51
  SPEAKER_00: Don't get me started.
• 7:53
  SPEAKER_00: But the next one would be metamorphic rocks, and these are types of rocks that also grow minerals.
• 7:58
  SPEAKER_00: So these are things that are heated up.
• 8:01
  SPEAKER_00: You take a rock, you put it under high heat, high pressure, and the atoms in that rock can rearrange themselves into different minerals.
• 8:08
  SPEAKER_00: And Chris, we have seen together an amazing example of metamorphic minerals growing in Gore Mountain, upstate New York, where we went on this camping trip several years ago, and I remember this is a mo actually uh a quarry, right?
• 8:22
  SPEAKER_00: They're quarrying this for beautiful, you know, countertops and things like that.
• 8:27
  SPEAKER_00: But it has these massive garnets in it, deep red garnets that are like softball or volleyball-sized garnets, and they have these beautiful white halos around them.
• 8:35
  SPEAKER_00: Do you remember this trip?
• 8:37
  SPEAKER_01: Oh, yeah, I remember those garnets are like the size of a baby's head.
• 8:42
  SPEAKER_01: I mean, they're big.
• 8:43
  SPEAKER_01: Uh, I remember driving up, going up to the top of this kind of mountain, and it's a dirt road, and it's it's a little sketchy, and we're just drooling at all of these.
• 8:52
  SPEAKER_01: We were very excited.
• 8:53
  SPEAKER_01: It's a beautiful rock, first of all.
• 8:54
  SPEAKER_01: It's a rock called Gabbro, and uh, so it's this black, coarse-grained rock that has these beautiful red garnets in it that are just enormous.
• 9:04
  SPEAKER_01: And we're drooling, and so we we get to the end of the road and we kind of stop and get out, and we're kind of milling around a little bit, not knowing exactly what to do because we didn't have permission to be there.
• 9:14
  SPEAKER_01: And all of a sudden, this black uh Chrysler 300 comes roaring up there.
• 9:18
  SPEAKER_01: That's right, and we're like, oh no, we're in trouble.
• 9:22
  SPEAKER_01: Yeah, we're in trouble.
• 9:23
  SPEAKER_01: Anyway, the the guy that gets out was the owner of the mine, and he was as happy and delighted to see us as you could possibly be.
• 9:32
  SPEAKER_01: The one he was the one like one of the nicest people on the planet.
• 9:35
  SPEAKER_00: He and like opened up the gate for us, said oh, drive down, take whatever you want.
• 9:39
  SPEAKER_00: I mean, we're walking around with these huge, like pieces of polished Gore Mountain garnet rock that have big garnets, beautiful white halos, big black rock, and we're just I mean, we're in heaven.
• 9:51
  SPEAKER_01: He took us down into it.
• 9:52
  SPEAKER_01: He's like, Oh, this is nothing, guys.
• 9:54
  SPEAKER_01: Let's go into the heart of this place.
• 9:56
  SPEAKER_01: So he takes us down there, and he did.
• 9:58
  SPEAKER_01: He said, You guys can have whatever you want.
• 10:00
  SPEAKER_01: I don't think he knew what that meant at the time.
• 10:04
  SPEAKER_01: I mean, we loaded up, we probably took two tons of rock back with us.
• 10:09
  SPEAKER_00: You're uh your your F-250 really hauled some rocks for us on that trip.
• 10:12
  SPEAKER_00: That was awesome.
• 10:13
  SPEAKER_00: It was working hard.
• 10:14
  SPEAKER_00: So we digress, but metamorphic minerals, minerals can grow in these what are called metamorphic environments.
• 10:19
  SPEAKER_00: It's solid state recrystallization.
• 10:22
  SPEAKER_00: That's what's going on in metamorphic environments.
• 10:24
  SPEAKER_00: The next one, Chris, is hydrothermal.
• 10:26
  SPEAKER_00: And you actually taught me a lot about hydrothermal environments on your field course that you have taught for what 20, 22 years now?
• 10:34
  SPEAKER_01: Yeah, a little over 20 years, you bet.
• 10:36
  SPEAKER_01: Hydrothermal, it's exactly what the name implies.
• 10:39
  SPEAKER_01: These are minerals that grow out of hot water.
• 10:42
  SPEAKER_01: Okay.
• 10:43
  SPEAKER_01: And so there's a variety of environments.
• 10:45
  SPEAKER_01: And you know, I taught you a little bit about this on the field course out.
• 10:48
  SPEAKER_01: And one of the places we go to in this field course is Yellowstone.
• 10:50
  SPEAKER_01: We spend four or five days in Yellowstone National Park.
• 10:53
  SPEAKER_01: And it's just a it's a great example of minerals that grow out of a hydrothermal because you have this hot spot and an abundance of water that circulates through the rock, and then when the conditions change, when the water becomes not so hot and it moves away from the heat source and so on, then it begins to precipitate minerals that were dissolved in that superheated water.
• 11:13
  SPEAKER_01: So that's one environment which this is common, but it's, you know, actually, this is way more common though, because uh Yellowstone's kind of an isolated geologic setting.
• 11:22
  SPEAKER_01: This is a very common environment, though, at seafloor spreading zones in the middle of the ocean, divergent plate boundaries, mid-ocean ridges.
• 11:30
  SPEAKER_01: That's where you get a lot of these hydrothermal mineral deposits that can be actually really quite important.
• 11:36
  SPEAKER_00: Yeah, and we'll we'll come back to what those divergent plate boundaries actually mean later.
• 11:40
  SPEAKER_00: But yes, hydrothermal mineral deposits are very important on earth for carbon cycling, carbon drawdown, all that kind of stuff.
• 11:47
  SPEAKER_00: The last environment in which minerals form are sedimentary environments.
• 11:51
  SPEAKER_00: And these are not hot water, but more like cool water environments.
• 11:55
  SPEAKER_00: You get these in places where you have really saturated water that is evaporating and you can form salt flats.
• 12:01
  SPEAKER_00: So, like the Bonneville salt flats where you see cars racing around Salt Lake City.
• 12:05
  SPEAKER_00: These are minerals precipitating out of water from the water column in a sedimentary environment.
• 12:11
  SPEAKER_01: Right.
• 12:12
  SPEAKER_01: I just want to point out, just from an experience standpoint, that a sedimentary environment is different from a hydrothermal environment.
• 12:20
  SPEAKER_01: Okay, that it's just something that can be confusing.
• 12:23
  SPEAKER_01: Hydrothermal involves this kind of superheated water that then precipitates minerals.
• 12:28
  SPEAKER_01: A sedimentary environment just involves salty water that is evaporating.
• 12:34
  SPEAKER_01: And as that happens, the water leaves and the salt stay, it becomes saturated with the salts that are dissolved in the water, and then it begins to just precipitate them down.
• 12:42
  SPEAKER_01: So it does not involve heated water necessarily.
• 12:45
  SPEAKER_01: Yeah.
• 12:46
  SPEAKER_01: In the sedimentary environment.
• 12:48
  SPEAKER_01: So and there isn't the second image in your stack just provides a brief summary of the four environments which minerals grow out of.
• 12:56
  SPEAKER_00: That's right.
• 12:57
  SPEAKER_00: So let's move on to the 10 most important minerals, what we call the rock forming minerals.
• 13:03
  SPEAKER_00: And these are, if you know these minerals, you can identify most minerals in most rocks.
• 13:08
  SPEAKER_01: Yeah, the term, actually, I think of it that way, rock-forming minerals should almost be hyphenated.
• 13:13
  SPEAKER_01: You know, it's like this, it's a vocabulary term.
• 13:16
  SPEAKER_01: Okay.
• 13:17
  SPEAKER_01: And all that it means is that look, most of the rocks that we see on the earth are formed from the same minerals, just in different combinations and different ratios and so on.
• 13:27
  SPEAKER_01: So what we're going to do, it's just basically a top 10 list, the top most abundant minerals that make up rocks on the crust of the earth.
• 13:36
  SPEAKER_00: All right, Chris.
• 13:37
  SPEAKER_00: So let's get into the rock-forming minerals.
• 13:39
  SPEAKER_00: And the rest of the images in the stack for this episode are images of these 10 rock-forming minerals.
• 13:46
  SPEAKER_00: So we just are giving examples.
• 13:47
  SPEAKER_00: The minerals, the way they look in nature can vary widely, but we're just giving some examples here to sort of help us along, right?
• 13:54
  SPEAKER_01: And the term rock-forming minerals just means that the common rocks that exist on the crust of the earth have a commonality.
• 14:01
  SPEAKER_01: They're made up of this kind of top 10 list of minerals that we're going to go through right now.
• 14:05
  SPEAKER_01: So, Jesse, go ahead.
• 14:07
  SPEAKER_01: What's the most abundant mineral on the planet?
• 14:10
  SPEAKER_00: Well, it's feldspar.
• 14:11
  SPEAKER_00: And feldspar is really a group, a category of minerals, again, but it's a framework silicate.
• 14:17
  SPEAKER_00: And so it's based on the silica tetrahedron.
• 14:19
  SPEAKER_00: It's the most abundant mineral in the crust, as you said.
• 14:22
  SPEAKER_00: And the cations that go into this structure are sodium, potassium, and calcium.
• 14:27
  SPEAKER_00: And we'll get into this in later episodes when we start talking about igneous rocks and metamorphic rocks in particular.
• 14:33
  SPEAKER_00: But the color of the feldspar changes depending on that ratio of calcium, sodium, and potassium in the thing.
• 14:40
  SPEAKER_00: Chris, what's number two?
• 14:42
  SPEAKER_01: Number two on the list of the rock-form minerals is quartz.
• 14:45
  SPEAKER_01: So the two most abundant minerals on the crust are quartz and feldspar.
• 14:48
  SPEAKER_01: Quartz is also a framework silicate.
• 14:50
  SPEAKER_01: It's SiO2.
• 14:51
  SPEAKER_01: All of the oxygens are being shared with nearby tetrahedrons.
• 14:55
  SPEAKER_01: Quartz is common in all three types of rocks that we have on our planet: igneous, metamorphic, and sedimentary.
• 15:03
  SPEAKER_01: Quartz is super stable.
• 15:05
  SPEAKER_01: It's a hard mineral.
• 15:06
  SPEAKER_01: It just not a lot happens to quartz once once it's formed.
• 15:10
  SPEAKER_00: That's right.
• 15:11
  SPEAKER_00: Uh, the next one, number three, are the micas.
• 15:13
  SPEAKER_00: And this is again kind of a group of minerals.
• 15:15
  SPEAKER_00: These are sheet silicates.
• 15:17
  SPEAKER_00: They have magnesium, aluminum, calcium as cations that go into the sheet silicates.
• 15:23
  SPEAKER_00: But these are really diagnostic because they're flaky in one direction.
• 15:26
  SPEAKER_00: We talked about this last episode that muscovite, you can kind of peel off sheets of a book of muscovite.
• 15:33
  SPEAKER_00: If you get a big crystal, it often occurs in this book.
• 15:35
  SPEAKER_00: And so we have things like muscovite and biotite are micas, and they're common in igneous and metamorphic rocks, sometimes in sedimentary rocks.
• 15:44
  SPEAKER_01: Yeah, not very often in sedimentary rocks.
• 15:46
  SPEAKER_01: And the reason is because sedimentary rocks are usually formed by water, one way or another, moving water, running water, that kind of thing.
• 15:54
  SPEAKER_01: And because of the flaky nature of mica, it doesn't hold up well to that, and so it breaks down rather quickly.
• 16:00
  SPEAKER_01: So it's not super common in sedimentary rocks.
• 16:02
  SPEAKER_01: But one thing about that is my students love to tear apart my muscovite and biotitan lab, you know, and I let them do it because I have tons of it.
• 16:09
  SPEAKER_01: You know, we've gone to the Black Hills and collected massive amounts of this stuff.
• 16:13
  SPEAKER_00: I would not like to be the janitor after a you know the lab for this class where you identify.
• 16:18
  SPEAKER_01: All right, number four, Chris.
• 16:20
  SPEAKER_01: Where are we at?
• 16:21
  SPEAKER_01: Yeah, number four on the list is uh the olivines.
• 16:23
  SPEAKER_01: And again, this is a group of minerals.
• 16:26
  SPEAKER_01: This is the single tetrahedron.
• 16:28
  SPEAKER_01: We did, you know, the frame with two framework silicates, we did a sheet silicate.
• 16:32
  SPEAKER_01: Now we're at the single tetrahedron.
• 16:34
  SPEAKER_01: And the dominant cations in this are iron and magnesium.
• 16:39
  SPEAKER_01: And so this group of minerals can be referred to in a couple of different ways.
• 16:44
  SPEAKER_01: One of them is called ferromagnesium, and that's because ferro is the what iron is, and uh the magnesium is magnesium.
• 16:52
  SPEAKER_01: So I tend to call this mafic, rich in iron and magnesium, but those two words mean the same thing.
• 16:59
  SPEAKER_00: So yeah, and these are common in basalts, they're common at high temperature, really kind of high temperature minerals, common in the mantle.
• 17:06
  SPEAKER_00: The next one, number five, is the pyroxene group, and these are single-chain tetrahedrons.
• 17:11
  SPEAKER_00: They're also ferromagnesian, meaning they have a lot of iron and magnesium in there.
• 17:15
  SPEAKER_00: You can also put some calcium in here as a cation to bond with this single chain of silica tetrahedrons.
• 17:21
  SPEAKER_00: And they're very common in igneous and metamorphic rocks.
• 17:24
  SPEAKER_00: Again, they're a high temperature mineral.
• 17:26
  SPEAKER_00: Number six, Chris, where are we at?
• 17:27
  SPEAKER_01: Number six, it's a group of minerals again called the amphiboles.
• 17:31
  SPEAKER_01: Now, here's the thing is that I typically in an intro intra-level class, like what this is, the amphiboles, the most common amphibole by far, is a mineral called hornblende.
• 17:43
  SPEAKER_01: So I I kind of I don't know, is that okay with you?
• 17:46
  SPEAKER_01: Like I use that interchangeably in my classes.
• 17:49
  SPEAKER_01: How do you do that?
• 17:50
  SPEAKER_00: Yeah, totally.
• 17:50
  SPEAKER_00: I think hornblende is a catch-all for the amphibole group.
• 17:54
  SPEAKER_00: And I think this is kind of an important thing to highlight is that we've been referring to these things as as groups, like feldspar is a group of different minerals, but it's a group of like three minerals, and they all have very similar relationships.
• 18:07
  SPEAKER_00: They all have the same structure.
• 18:08
  SPEAKER_00: There's just slight tweaks in the chemistry that makes the difference here.
• 18:12
  SPEAKER_00: So there's the cations.
• 18:14
  SPEAKER_00: It's the changing the ratio of cations a little bit, but they share a ton of similarities.
• 18:18
  SPEAKER_00: That's why we say feldspar is a mineral, one of the 10 most abundant minerals, right?
• 18:22
  SPEAKER_00: So um, yes, absolutely we can use horn blend for a catch-all for amphiboles.
• 18:26
  SPEAKER_01: So the amphiboles, the horn blends, those that's a double chain silicate.
• 18:30
  SPEAKER_01: And then next on the list are the clay minerals.
• 18:32
  SPEAKER_01: And this is actually a sheet silicate, much like muscovite and biotite, but it doesn't quite look like muscovite and biotite.
• 18:40
  SPEAKER_00: Yeah, clay minerals are, as you probably are thinking, they are abundant in the soil.
• 18:46
  SPEAKER_00: We have clay layers in the soil.
• 18:47
  SPEAKER_00: One of the very common ones is called kaolinite, and they form typically as other minerals, particularly feldspars, break down.
• 18:55
  SPEAKER_00: So when feldspars get into streams, they start to chemically break down, they often form clay minerals.
• 19:00
  SPEAKER_01: Okay, so I want to point something out a second here.
• 19:03
  SPEAKER_01: We're number seven in our list, right?
• 19:05
  SPEAKER_01: And we haven't gotten out of seven out of the ten rock-forming minerals.
• 19:10
  SPEAKER_01: We're still in the silicates.
• 19:11
  SPEAKER_01: Okay, we haven't moved out of that.
• 19:13
  SPEAKER_01: Now we move to number eight on the list of the rock-forming minerals, and finally we get away from the silicate structure group of minerals.
• 19:22
  SPEAKER_01: So number eight is calcite, which, as we referred to a little bit earlier, is a carbonate mineral.
• 19:29
  SPEAKER_01: It has calcium as the cation, and then the dominant anion is CO3.
• 19:34
  SPEAKER_01: So the CO3 is what we call in chemistry a carbonate.
• 19:37
  SPEAKER_01: So calcite is a carbonate mineral, it's a very important mineral.
• 19:41
  SPEAKER_01: Okay, it's number eight on the list, but we don't, I don't want to like, I don't want to shortchange calcite.
• 19:46
  SPEAKER_00: This is hugely important, definitely.
• 19:48
  SPEAKER_00: Uh, it is the mineral that's very important for the carbon cycling.
• 19:52
  SPEAKER_00: It's really the mineral we talk about if we talk about carbon capture and storage.
• 19:55
  SPEAKER_00: It's calcite we're talking about that's storing that CO2 in it.
• 19:59
  SPEAKER_00: And in the natural environment, it's taken out of water by marine organisms to make their shells, right, Chris?
• 20:04
  SPEAKER_00: Most of marine shells are either calcite or aragonite, very similar partner to calcite.
• 20:10
  SPEAKER_01: Very similar.
• 20:11
  SPEAKER_01: Yep, that's right.
• 20:12
  SPEAKER_01: And um calcite is a pretty easy mineral to identify.
• 20:16
  SPEAKER_01: You'll do this in lab because calcite is effervesces very it fizzes a lot when you drop hydrochloric acid on it.
• 20:23
  SPEAKER_01: Just a little tiny drop of acid on it, it'll fizz like alkyl seltzer in water.
• 20:27
  SPEAKER_01: Um, and it also has uh I don't know, yeah.
• 20:31
  SPEAKER_00: You're I'm looking at you because I you know where I'm going at this, don't you?
• 20:34
  SPEAKER_00: It also has this interesting property that when Chris crushes it up and puts it in his water bottle, it cures his heartburn.
• 20:40
  SPEAKER_00: It does.
• 20:40
  SPEAKER_00: It's the exact same reaction that's going on with the hydrochloric acid, but just in your stomach.
• 20:45
  SPEAKER_00: You know, Chris is hold on.
• 20:46
  SPEAKER_01: I'm a little offended by that because that's pretty clever, actually, right?
• 20:50
  SPEAKER_01: I mean, I mean if you're in the field, you're you're working, you know, you you can't do any geology work in the field without having a hammer, right?
• 20:58
  SPEAKER_01: And but you, you know, you ate tacos the night before, and and so uh sometimes you get a little a hot chest, you know, you got the heartburner thing going on, and all you have to do is take calcite or limestone, because that's what limestone is made of, is the mineral calcite, crush it up, put it in an algae bottle with water, and and drink it, and bam, gone.
• 21:19
  SPEAKER_00: Heartburn gone.
• 21:20
  SPEAKER_00: Well, you Chris, Chris, you can do this.
• 21:23
  SPEAKER_00: We can't pass this recommendation along for uh liability reasons to anybody listening to this, but it fixes your problems.
• 21:29
  SPEAKER_00: Like it's just it's solving problems, Jesse.
• 21:32
  SPEAKER_00: You are a problem solver, that's right.
• 21:33
  SPEAKER_00: So number nine, dolomite, a very close relationship with carbonate.
• 21:39
  SPEAKER_00: It is partly calcium in there, but also magnesium.
• 21:42
  SPEAKER_00: So we have C A, Mg, calcium, and magnesium that are both bonded to this carbonate and ion, this um carbonate anion.
• 21:50
  SPEAKER_00: So C A Mg CO3 is the formula for dolomite.
• 21:55
  SPEAKER_00: And so this is a little bit different from calcite when you're identifying in it, is that it magnesium.
• 22:00
  SPEAKER_00: Magnesium is smaller than calcium.
• 22:01
  SPEAKER_00: So they're actually little vugs present in dolomite when compared to calcite.
• 22:06
  SPEAKER_01: That's right.
• 22:07
  SPEAKER_01: And the other thing that you can use to identify dolomite from calcite, because they look very, very similar, is that because of the presence of magnesium in the structure of this mineral, it is less reactive than calcite is.
• 22:20
  SPEAKER_01: And so when you put acid on it, you put a drop of HCl on it, it won't fizz.
• 22:25
  SPEAKER_01: What you need to do then is take a scissors or a piece of metal and scrape up a little bit of powder, then drop acid on it, and it'll fizz like a flat pop.
• 22:33
  SPEAKER_01: It'll just kind of go bubble, bubble, bubble rather than fizzing like crazy like calcite does.
• 22:39
  SPEAKER_00: Yeah.
• 22:39
  SPEAKER_00: And it's not as good for your hardburn either, huh, Chris?
• 22:41
  SPEAKER_00: So it's not.
• 22:43
  SPEAKER_00: The last number 10, we kind of have two in here because they're very related and they form in related environments, is halite and gypsum.
• 22:50
  SPEAKER_00: Halite we all know as rock salt or NACL.
• 22:53
  SPEAKER_00: And gypsum is a sulfate.
• 22:55
  SPEAKER_00: They both precipitate out of both evaporating salt water or any sort of very saline environments.
• 23:02
  SPEAKER_00: They'll be precipitating out of water columns.
• 23:05
  SPEAKER_01: That's right.
• 23:06
  SPEAKER_01: So these two minerals would form out of what we referred to earlier as the sedimentary environment, out of evaporating salt water.
• 23:13
  SPEAKER_01: So well, Jesse, that is a wrap for this episode.
• 23:18
  SPEAKER_01: In review again, what we did today was we talked about the other mineral groups based on the dominant anions that are present, things like the carbonates, the sulfates, and the phosphates.
• 23:28
  SPEAKER_01: We then moved on to and talked about the different environments in which minerals form.
• 23:33
  SPEAKER_01: There are four, and there's an image in your stack that gives a review on this.
• 23:37
  SPEAKER_01: And then we rounded out this episode by talking about the term rock-forming minerals.
• 23:43
  SPEAKER_01: It's basically a top 10 list of the minerals that make up most of the rocks that exist on the crust of the earth.
• 23:51
  SPEAKER_00: Okay, Chris.
• 23:52
  SPEAKER_00: Before we end it, you ready for one question?
• 23:55
  SPEAKER_01: I'm ready.
• 23:56
  SPEAKER_01: This is my favorite part, by the way.
• 23:58
  SPEAKER_01: I I love this part because you get this silly look on your face, like, I don't know.
• 24:02
  SPEAKER_00: I'm excited.
• 24:03
  SPEAKER_00: I'm excited to test you.
• 24:04
  SPEAKER_00: After all the years you tested me in high school, I get to test you back a little bit.
• 24:08
  SPEAKER_00: Um, I just have one question for this episode.
• 24:11
  SPEAKER_00: What controls the number of minerals that are formed on Earth?
• 24:15
  SPEAKER_00: A.
• 24:16
  SPEAKER_00: The amount of elements in the earth.
• 24:18
  SPEAKER_00: B, there's not really a limit to the number, or C, there are only a few structures that are stable in different minerals.
• 24:27
  SPEAKER_00: What controls the number of minerals that are formed on Earth?
• 24:31
  SPEAKER_01: Do you mean that okay, this is a very poorly worded question?
• 24:36
  SPEAKER_01: And um like I don't so by number of minerals, do you mean the variety of minerals?
• 24:42
  SPEAKER_00: Yeah, the number of different minerals, not the number of different mineral grains.
• 24:45
  SPEAKER_00: Yeah.
• 24:45
  SPEAKER_00: Number of different minerals, categories or types of minerals.
• 24:49
  SPEAKER_01: Okay, so alright, repeat my answers again then.
• 24:52
  SPEAKER_00: Okay, I'll repeat, I'll go back and repeat the whole thing.
• 24:54
  SPEAKER_00: What controls the number of different minerals that are formed on Earth?
• 24:58
  SPEAKER_00: A, the amount of elements on Earth, B, there's not really a limit to the number, or C, there are only a few structures that are stable for different minerals.
• 25:08
  SPEAKER_00: This is more of a thought-provoking question.
• 25:11
  SPEAKER_01: Yeah.
• 25:12
  SPEAKER_00: I would go with C.
• 25:15
  SPEAKER_00: Okay, so that would probably be technically correct, I think.
• 25:18
  SPEAKER_00: I was really going for B.
• 25:20
  SPEAKER_00: There is not really a limit to the number because people are discovering new minerals every year.
• 25:27
  SPEAKER_00: There's several thousand minerals that have been discovered, and new ones are being discovered all the time.
• 25:32
  SPEAKER_00: So if you imagine all the elements in Earth, we can sort of arrange them all in very different ways.
• 25:37
  SPEAKER_00: So, you know, it's kind of a limitless thing, the different types of minerals.
• 25:43
  SPEAKER_00: If we make a new slight recipe, we can make new minerals.
• 25:45
  SPEAKER_01: But I would say this, Jesse.
• 25:48
  SPEAKER_01: Your your question has potential.
• 25:50
  SPEAKER_01: Okay, it needs to be reworked.
• 25:52
  SPEAKER_01: All right.
• 25:53
  SPEAKER_01: Okay.
• 25:53
  SPEAKER_01: That that needs to be it's a I like your thought.
• 25:56
  SPEAKER_01: I like where you're going with it, but yeah, I think it needs some reworking on that.
• 26:00
  SPEAKER_00: Okay, I'll I'll put more effort into the next one then.
• 26:03
  SPEAKER_01: All right, here we go.
• 26:04
  SPEAKER_01: Good deal.
• 26:05
  SPEAKER_01: That was a good episode.
• 26:06
  SPEAKER_01: We'll see you next time.