Great Rocks, Summer Excursions, and Confusing Minerals

Jesse Reimink: Welcome to planet geo the podcast where we talk about our amazing planet, how it works and why it matters to you.

Oh, well I can see I've got fun, Chris today.

Chris Bolhuis: you always have fun, Chris,

Jesse Reimink: have em,

Chris Bolhuis: how you doing Jesse Reimink?

Jesse Reimink: oh, Christopher Bohuis. We're back at it. After a long time. It's been a minute.

Chris Bolhuis: This I think is our longest break isn't it? I haven't seen you in a long time and you know, you you, uh, I missed you too. You haven't improved though. I'm looking at you right now and

Jesse Reimink: this summer has done me dirty here a little bit. It's has not

Chris Bolhuis: the field took its toll. Tell you that.

Jesse Reimink: I got COVID the whole thing, you know, just took its toll, but you know, it's all

Chris Bolhuis: Hey, cuz it's been a while. Jesse. Let's do some intros.

Jesse Reimink: Let's do it. You are Chris Bolhuis. My former high school teacher high school earth science teacher, extraordinaire from the great state of Michigan. You taught me. Uh, ninth grade earth science, uh, geology, basically advanced placement geology. Um, another class that I really didn't do much in I think, and field

Chris Bolhuis: oh, come on now.

That's not

Jesse Reimink: field course

Chris Bolhuis: not true.

Jesse Reimink: well, my independent study, you know, I did a few things.

Chris Bolhuis: that hurt just a little bit right there. Yeah. Yeah. Okay. Well, I was gonna say a lot of good things about you, but your Dr. Jesse Reimink, you went to hope college got your bachelor's in geology, and then you went to the university of Alberta in Canada and got your PhD in geoscience. And now you, I don't somehow you landed a great job at one of the premier geology schools in the country, Penn state university. So that's awesome. I, I do have to say, first of all, Yeah, you learned a lot in geology, but you're right. You didn't do much because you, you were more like a bump on a log than anything else. I mean, I I'd seriously had to check your, pulse to make sure you were still with me. I did that a lot. I

Jesse Reimink: Yeah, I, I do

Chris Bolhuis: so. Yeah.

Jesse Reimink: pulse

Chris Bolhuis: You had no personality back then. I don't know what happened, but

Jesse Reimink: now. I'm not shy anymore. um, so like we alluded to, it's been a while since we've sat down and recorded. And we've both had pretty daresay, adventurous summers out there in the field.

Chris Bolhuis: Yeah, but hold on, before we jump into that, though, you had something else you wanted to talk about that we have going on. So why

Jesse Reimink: yeah, totally. We updated our website. So before we get into what we're talking about today, we updated our website. We also added in a donation support us link. And, uh, so you can go there. You can check out our website, planet geo cast.com and, uh, you can support us. We're. Making any money on planet geo, uh, we're just, uh, burning money. And so help us not burn as much money doing this, I guess, would be, the exercise, you know, donate don't it doesn't really matter to us, but, uh, we like to support. We've had a couple already and we really, really appreciate it. So, uh, planet geo cast.com, it's a mostly updated website there and stay tuned to that space. There'll be some more stuff coming at you in the next month. Probably.

Chris Bolhuis: Um, yeah, we do. Jesse and I we've been working really hard on a new project that I think if you like this, I think you're gonna love that. we're really excited about it. That should be coming out in the next month,

Jesse Reimink: Yeah, totally. we're, uh, tidying up some things and it'll be a work in progress for a while, but it's coming at you in the next couple weeks or a month here. So stay tuned to the podcast stream. We'll talk about that more there, back to today, Chris, we've been.

I don't know, uh, adventuring out and about we've been out

Chris Bolhuis: So hold on, Jesse. let's give 'em a rundown about where we're gonna go today.

Okay.

Jesse Reimink: Okay. Good, good point, Chris. I'm just too excited. I'm gonna launch into stuff. I mean, you know, just ready to launch into it. Well, first of all, you teased me a little bit before we hit record here about a very funny story, about yourself that I think we're gonna get to first. I'm really excited to hear this, , but what we're really talking about is that you and I have been out in the field. Been doing geology of different kinds. You've been teaching the field course. You've been out with your family. I've been up in the Arctic Canada doing field work. And so we're gonna kind of summarize that a little bit, talk about what we saw. And then we also had several people reach out via Facebook, emails, Instagram, and sort of ask about mineral identification or commonly confuse minerals. So we didn't have a lot of time to put together a, a. Episode on just that, and this is a huge topic, so we're just gonna go kind of off the cuff, right Chris, like what's on the top of our head when people say, what are the commonly confused minerals? And we're just gonna briefly summarize a couple of them. Is that a fair summary?

Chris Bolhuis: You bet. We're gonna do a much more detailed thing on this. We need to really like do something with, alright, how do you identify rocks in the field? And, that's a hard thing. It's complicated. We're gonna, tackle that coming up in the next, well, little while.

Jesse Reimink: Yeah. And it's a huge, I mean, it's a lifetime of learning how to identify rocks and minerals in the field. but we can give a bit of a guide. So we'll sort of lead into that a little bit, but Chris I'm itching to hear what happened today.

Chris Bolhuis: So, um, today was the last day that we had at, you know, we're back to school now. So we're back in the grind. You and I are kind of easing our way back in the routine. Right. We had some students in the building today just doing an orientation. It was the freshman, you know, so they're, young kids and so on. And we start on Monday with, everybody's there. Full on now, but so I'm walking around the corner. Okay. Now I gotta set the stage cuz now everybody knows what I look like. I'm 50 years old. I have a go tea. It's mostly , it's mostly white. Um, but Matt, you know? Yeah. I shaved my head. Yep. That's that's right. Um, and so I walk around the corner and a kid who's walking next to another teacher, looks up at me his eyes light up. and he says, Grandpa GORT

Jesse Reimink: Oh, my God. Oh, that is so good. Oh, a nickname has been established for eternity here. Grandpa GORT.

Chris Bolhuis: Grandpa GORT. Yeah. I looked I'm like, excuse me, what? And he's like, oh, oh. And he recognized that I'm not his grandpa And

Jesse Reimink: oh, this is gold dust.

Chris Bolhuis: said, you look just like my grandpa GORT.

Jesse Reimink: this is, this has made my week. I was having a rough stressful week and this has made it Chris. this is gold dust. I gotta write this down. So I don't forget it. Grandpa GORT.

Chris Bolhuis: Grandpa GORT, uh, you know, Jesse, look, what do you do in a situation like this? Right. I'm just gonna lean into it.

Jesse Reimink: yeah, you

Chris Bolhuis: you know, uh, so it's, there's no way out I gotta embrace it.

Jesse Reimink: It's kinda like when you like, you know, trip on the hiking path, you just gotta kind of jog it out and pretend like you didn't trip. Right.

Chris Bolhuis: that's right. I,

Jesse Reimink: and

Chris Bolhuis: Hey, I taught you that. I taught you. Okay. You, you don't know that I did. I taught you this. Well, come on now, when those rocks reach up and grab your ankles and you start tripping, you just jog it out, like you meant it to happen. So, yeah, that's that's my

Jesse Reimink: crap a court. All right. Well, we'll see if we can build your ego back up here, Chris, a little bit

Chris Bolhuis: Okay Well, Hey, Jesse, let's get down to business. Um, let's start with you. What, what kind of cool GE, where have you been? What kind of cool geology did you see this summer? that our listeners might wanna hear.

Jesse Reimink: Yeah. Well, I had a pretty good summer. As far as travel goes. It was a fairly. um, well, it took a lot of organizing, but I taught our undergrad field course. Our Penn state field camp goes out. The course is six weeks total. Uh, it goes, drives from Pennsylvania all the way out to Idaho and then down to Utah, um, they spend a lot of time doing a variety of different stuff, but I flew out for a week in Idaho. Right by the craters of the moon national monument, we looked at a metamorphic core, complex and mapped, some faults and some interesting rocks there. So that was one week. I also had a conference in Hawaii. Big bummer

Chris Bolhuis: Oh, my gosh. Yeah.

Jesse Reimink: some basalts

and some beaches. couple.

Chris Bolhuis: red lava?

Jesse Reimink: I did not see red lava. I didn't have any time, unfortunately, to do any touristy stuff. I was at the. I went to the beach a day, uh, and you know, did the beach thing. And then we did a tour, a driving kind of tour, driving, hiking a little bit, but we were on the big island and in Honolulu basically. And then the conference was the rest of the week. And then I had to head back to Pennsylvania because I was organizing a field campaign into the Arctic of Canada. I was up there for two weeks with a PhD student who just started and a couple colleagues way up, in the Arctic circle, collecting rocks from up near the Arctic coast. So that was really fun, uh, and tiring. And we got back a couple days ago, so I'm recovering from that a little bit still. So that was my summer really?

Chris Bolhuis: So did you collect some big old rocks from, uh, Northwest

Jesse Reimink: Oh man. We took back well, they're in shipping right now, but probably a thousand pounds of samples and some of them are.

Chris Bolhuis: did you really? Holy crap.

Jesse Reimink: Yeah. There's like, you know, 25, 5 gallon pales of, of rocks. Um, this is gonna be a.

Chris Bolhuis: What's that cost to ship back?

Jesse Reimink: Well, a very small amount compared to the total cost of the field work. So we had a, a float plane that was flying us around collecting samples. This was in this, um, we've talked about it before, but looking for ancient diamonds in ancient sediments. So this is that project. So we are kind of flying around sampling a bunch of different sediments, ancient sediments, and we're gonna look for diamonds in them and also prospecting for really old rock.

Chris Bolhuis: cool. So I have to ask this question then you've been a lot of different places, seen a lot of different rocks, then what's the favorite rock? That you've seen this, uh, this summer.

Jesse Reimink: this was, yeah, there's no question. This was the best one. We basically one. We flew in this little tiny float plane. It's like a five seater pilot plus four people. And we couldn't fit any rocks. We had four people, but three of us flew up to the Arctic coast. So we landed on the Arctic ocean in this little bay and the outcrops. There are ancient, gneiss exposures. G N E I SS the Rox I study and right on the coast, there's no lichen cuz the, sea ice scours it all away and the sea spray doesn't allow li.

Chris Bolhuis: lichen is that biology that likes to cover up

Jesse Reimink: Oh,

Chris Bolhuis: geology for everyone that doesn't know that.

Jesse Reimink: Oh. And in Northern Canada, lichen is everywhere and it gets in the way of everything. And these really beautiful rocks are covered in lichen. You can't see shit. So this coast, we landed. I'll send you a picture of this and, maybe we'll share one on the social media feed here, but these rocks. This was toothpaste rock. I mean, this stuff was spectacular. Like different fold patterns. It was just toothpaste. I mean, this is highly metamorphoses NICES that are folded bent faulted, and we're just walking like kilometers along this Arctic coast. we had a stunningly beautiful day up there. It was like 75. it was flat calm water. We collected samples all day. Then we took a dip in the Arctic ocean. I mean, it was just this. It was geology porn. I mean, I described it to our float play pilot. He was like, oh, what kind of rocks are you collecting here? I was like, well, to be honest, the last two hours, we've just been wandering on taking photos. This is geology porn. And he looked at me kind of quizzically. He is this like 65 year old guy. He looked at me quizzically. And I was like, you know, the, the rocks that get all the geologists kind of worked up he got a good chuckle lot of that. So

Chris Bolhuis: He'd never heard

Jesse Reimink: you'd never heard the term. No. Yeah. He's been around geologists a lot before, but, uh, anyway. Yeah,

Chris Bolhuis: Wow. Um, alright. So I have a question then. Am I gonna get one of these rocks? I don't require a big piece, but I, I feel like I deserve a piece.

Jesse Reimink: Yeah, I think you, I think you might, yeah, we'll have to, we'll work something out on the side here. Yeah, we can do that.

Chris Bolhuis: Well, okay. But I don't need your lever. Right. All right. You just, need

Jesse Reimink: Chris.

Chris Bolhuis: I need to look. I need a good

Jesse Reimink: I don't collect believe right anymore, man. this is serious stuff, but yeah, I mean, we've got some amazing there's some, the problem is, is the scale, like the hand sample. when you have a spectacular rock, a hand sample, doesn't really do it justice. Like you need a countertop slab cut out of the outcr, right? It was really hard to find even a big sample, like one that you could carry that really showed. The beauty and the complexity of these rocks, it just doesn't do it justice

Chris Bolhuis: you. Yep. Yeah. You know, you and I we've evolved in our collecting habits. we are into massive rocks. I mean, the bigger, the better that's, that's kind of where we're at right now. So I get it. Yep.

Jesse Reimink: These rocks were just stunning and it really was when rock is heated up to high temperature and at high pressure it's toothpaste and it can be squished and bent and folded and deformed, and it just flows like toothpaste. these are all crops really showed that really.

Chris Bolhuis: That's great. I want everybody to understand how big of a deal it is for him to say this, because I've gotta assume that you saw some pretty spectacular POI Hoi lava flow texture Hawaii.

Jesse Reimink: we did see some, there was some pretty cool stuff. We didn't go to any of like the really recent, eruptions, but we did walk through the cliffs where you can kind of go through and you can see a cross section through the PO ho ho

Chris Bolhuis: Describe what POID looks like a

Jesse Reimink: Yeah. Poya is this flow pattern? It looks like ropey texture on top of AAL when the lava flow erupts and the top of it, the kind of skim cools. So the very surface of it is cool and solidified, , but just underneath the surface, it's still liquid or it's still lava. Then it kind of rolls the top pattern and you get this really ropey texture to it. It's just beautiful

Chris Bolhuis: it's it's so cool. It it's spelled P a H O E H O E. And it's pronounced pahoehoe and it's a flow texture. It's black, smooth ropey, kind of this twisted braided appearance. It's really spectacular rock. And so for you to say this other one, like that, that means that that's, that's pretty, pretty awesome

Jesse Reimink: We actually saw PO ho in the craters of the moon national monument, where we went there for a day during the field camp. And that's where you taught me a lot of stuff. I we were driving along the sneaker of plane and I was having flashbacks to in high school. We've talked about this before. I think when I was sitting, I think I sat in the front of the bus and this was the moment I really decided understanding the earth. Really just what I should do. This is a really cool thing, cuz I remember we were driving from Yellowstone to Craters of the Moon National Monument, through the Snake River Plain, this huge, just open plane and you were driving a big yellow bus. You're driving. Students are all in the back two to a seat. Basically. I wandered up to the front and I sat on the steps, you know, the front steps, the rubber steps of the bus. And I was just asking you questions and then you, you kind of push me a bit and you're like, Hey, what are we driving through? Right. This is big valley. We just left this big volcano. What are we driving through now? And it took me forever to figure it out and I couldn't figure it out. But anyway, I was having flashbacks about this, about as we were going to cratos in the moon, but we saw amazing pahoehoe there too. Like we saw, you know, in 2000, whatever, I won't mention it, but 2000, whatever, when I was in high school,

Chris Bolhuis: You know, that brings up a point. You know, we've done Yellowstone. We talked about the GL stone, but we haven't done the end of the story really of Yellowstone, which is really craters of the moon. It's an amazing story. That park is so underrated that I think that we probably need to do some justice to it and do an

Jesse Reimink: I would agree. I would agree. Which leads nicely, Chris, into what have you been up to this summer? I mean, you've been there presumably this.

Chris Bolhuis: This has been I think the busiest summer that I've had, I, right after school, let out officially, Jenny got certified in woofer wilderness, first responder training. . And we were home for, I think four days that was just enough time to like regroup and equip and get everything set up for the field course that I teach out west. So took 26 high school seniors, some of our best, out west. And, um, it was, you know, we went to the places, we talked a lot about 'em and, and we were pretty much right on with the releases that we had. We released devil's tower. we released the Badlands while we were

Jesse Reimink: me, interrupt. If you haven't listened to those episodes, go back a few episodes several weeks ago, a couple months ago, and you can listen to those and sort of follow along the field camp that Chris leads and, uh, learn about the geology of those areas. Anyway, go, sorry. Keep

Chris Bolhuis: Yeah, that's right. So yeah, Badlands black Hills, then devil's tower. And then from there, we, we head straight to the Tetons and the Tetons this year, Tetons never disappoint I'm in love with them. Oh, there's more to come on that in a little bit. But then we went to Yellowstone and this was interesting because Yellowstone recently had these massive. 500 year event, at least, this flood event that wiped out the Northern part of the park and the road system and the infrastructure there. Um, you know, there's lots of sad stories that go along with that, but, you know, we were able to do everything that we really wanted to do. from there, went to glacier and glacier national park is amazing. We did an episode on that a long time ago now. Um, but glacier's just a cow. it's an amazing place. And we spent actually all of our time in, a place in the Southern part of the park called two medicine. It's probably the least busy part of glacier national park. And two medicine is good medicine. I love it. It's absolutely amazing. In fact, one of my former students she's the captain of the boat on two medicine lake. And so she takes tours every day, you know, and she runs a crew of like five people. Um, so she took us out, not the group, but she took, my wife and, you know, Andrew, our, our friend and my teaching partner and his wife took us out in the lake in the evening and threw a couple lines in the water. Caught a couple late trout.

Jesse Reimink: Yeah. Nice. That's awesome. this is all on the, the field course. Right. And then where did you guys go on your family trip? You guys did a family trip after that. Is that right?

Chris Bolhuis: Yeah, we were home for three days and then we went to, Colorado, actually, we went to Denver area. And, uh, we caught a concert at red rocks, saw David Gray. It was amazing. And then we, got up really early the next day after the concert and, We hiked up to the Boulder field, um, which is about 12,900 feet up and we made camp. And then this is inside Rocky mountain national park, and then we, uh, we climbed longs peak. The next next morning, got up at the crack of Dawn and climbed

Jesse Reimink: beat

Chris Bolhuis: done that together. So it brought back members. Heck yeah, it was, oh yeah, it was awesome.

Jesse Reimink: great. I, I do remember we had a very rainy dreary day, but we managed to have our whiskey at the top. That was, that was totally good. That was

Chris Bolhuis: We did. Yeah. I didn't have any of that with us because we took. So my daughter on this trip got engaged. and so that happened in the Tetons, but I knew it was gonna happen. So my soon to be bonus son was with us on this trip and, uh, yeah. Yeah. Yeah. So, uh, he is not used to this kind of exposure. You remember, longs peak has a, it's not a hike, you know, that it's got a fair amount of exposure on that. And it was really interesting watching him move

Jesse Reimink: yeah. It's uh, that can be a bit intimidating that hike for sure. You gotta not look. There's some parts where you don't look down too much.

Chris Bolhuis: That's right. So the answer to, to the question about favorite rock is actually on this hike. I'll come back to that in a little bit. Then we went to the Tetons. We spent about two weeks in Tetons. My bonus son, um, he proposed, we hiked up to the base of the middle Teton. And made camp. And then at sunset is when he proposed to her. And then the next morning we got up at the crack of Dawn and climbed the middle Teton and yeah, it was awesome. So,

Jesse Reimink: That's very cool.

Chris Bolhuis: like, uh, you know, you talk about like this toothpaste kind of texture in these metamorphoses rocks. , I saw a lot of that in the Tetons. I took a lot of pictures of it. I I'll share those with you later on. Just absolutely like you look at these rocks all you can think about is how you want one in your yard. You know, I wanna stare at that every single day. they're so unbeliev. They really are. Um, and you know, there just, there was a lot of that.

Jesse Reimink: That's a cool place. That's uh, great, great summer. So the rock let's, let's talk about the rock. it was the long speak. One

Chris Bolhuis: Yeah, the, it was on longs peak and, and I think you have to remember this. It is this Peric granite.

Jesse Reimink: So let me interrupt there. a photic granite. Granite is a rock type. It's the light colored intrusive rock. So it's a magma that cooled underneath the surface. The grains are fairly large. You can see them with your naked eye, but photic means it has two different grain sizes. It has really big grains and moderately big grains. And so photic is a term. That just says this granite has two different crystal sizes in it, some really big ones. And then the background will be visible pieces of usually quarts and felt spar and bio things like that.

Chris Bolhuis: Yeah, well said my young age, that was

Jesse Reimink: Thank you

Chris Bolhuis: Um

Jesse Reimink: Continue. You may continue now.

Chris Bolhuis: but here's the thing, right? And this is what I wanna talk to you about actually, is that, In a classic way. A photic rock is thought to form. You said two distinct grain sizes, right? Big grains. And then smaller grains within the same rock. Well, rate of cooling is almost always the factor that determines grain size and IUs rock. So if it cools slowly, the minerals have time and they get larger. Right. So what you would have with this. That's thought to be that you have this slow, slow cooling, the crystals get big. And then this magma moves closer to the surface where it cools faster, and, and then the grains get smaller. But the thing is about this is that the big crystals in this, these Feld bar crystals, they're not randomly oriented, like an igneous rock should be these have a definite pattern to them. They are all lined up. In the same direction and that's what it makes it so cool. But what are your thoughts on that?

Jesse Reimink: well, I have some thoughts. They're not the most, uh, informed, but this is a hot topic in the science of understanding granites right now, like really hot topic. Traditionally, I would say the textbook model would say that those big grains. In a magma, they cooled in a magma, they were growing in a magma and then the magma started to flow a little bit. You know, it kind of moves from one side of the magma chamber to the other, and that would orient all the grains. And so you could see this, I've even seen this in Washington, DC, like a lot of the monuments. Like the world war II Memorial in Washington, DC on the national mall is made of ayora. Granite like the rock is a perforate granite. You can see those big Feld spa grains are aligned in a certain direction. They're all kind of pointing in one direction. It's really beautiful. The idea would be the traditional idea would be that the magmas kind of oozing it's sort of slowly flowing a little bit and then the grains get aligned by that flow. There's an alternative interpretation. Suggest that that's all what we call sub Solidus or solid state chemical. Movement. So, sort of fluids flowing through the rock that could crystallize those things. That's a little bit of an oversimplification of the model, but that that's happening after the rock has solidified. And then those grains are growing much later and at lower temperature, not magnetic temperatures, but still high temperatures, you know, 400, 500 degrees centigrade, but not magmatic temperatures. And so there's a debate in the literature about that. And actually this is a huge. Rabbit trail to go down, but we should probably try and find somebody to interview about this, cuz it's a fascinating problem in geology.

Chris Bolhuis: It looks to me. I mean, when you look at this rock, it looks like it was flowing as it solidified. So what you said, like theory, number one that's the way it looks. That makes the most

Jesse Reimink: Totally. Totally.

Chris Bolhuis: and these crystals are huge. some of them are over an inch long

Jesse Reimink: than your thumb,

Chris Bolhuis: Oh yeah. They're they're so, and they're pink and they're white and various shades in between, some of 'em are orange, bright orange, so they're beautiful. And because it's not particularly common. That was my favorite rock that I saw this summer was easily the long speed granite, for sure.

Jesse Reimink: Those rocks are so spectacular to see in person and, you know, you get the fells FARs and they kind of Glint the cleavage direction, sometimes glimpse at you if you walking past. So it looks like it's cliff, side's kind of like Glint and shining at you like little diamonds, kind of sparkling out. You go up close and it's a big felt spa that, you know, when it hits a flashes at you. It's be.

Chris Bolhuis: And it's all over too. I mean, you're stepping over all this rock So when you're walking, your eyes are down, so you don't trip, you know, cuz it's really a Rocky rough trail and you, so this rock is just literally, that's all you see all day long. It's really cool. So

Jesse Reimink: cool That's a, that's an excellent one, Chris. Hell of a summer, so, let's sort of wrap this up by talking about a few minerals, commonly confused minerals that. We could give a few tidbits about how to distinguish minerals that look alike. And we've had, again, just to reiterate, we've had several requests from listeners in this sort of general space of how, you know, we like collecting minerals. We like collecting rocks. We're out there, help us identify these things, cuz it can be massively confusing. And I can attest to that. Anybody who has gone out, looking at rocks can attest to how difficult it can be to. Identify specific minerals. So we're gonna break down two different pairs of things that are commonly confused. This is just off the cuff. We haven't really put a lot of thought into just, you have a vast experience with what people get wrong. in the field, right? the expert on here on like what confuses people, what throws people off? So what do you think? What do, what

Chris Bolhuis: Yeah. first of all, I wanna say that like, if you're interested in this kind of thing, really, and, and some of our listeners clearly are because of the questions that we're getting, then you need to just go, uh, get online and buy yourself a hand lens. this little magnifying, geology, little hand lens, it folds in on itself to protect itself. You put a little, uh, like a shoestring around it and, and you wear like a necklace.

Jesse Reimink: cost you 10, 15 bucks. You can buy $40 ones, but 10, 15 bucks will get you where you want to go on this.

Chris Bolhuis: That's right. They're they're not expensive at all, but they're so helpful. And in doing this kind of field identification of, of minerals and allowing you to see, not only just identifying the minerals actually, but also identifying rocks, classifying rocks as whether it's igneous, metamorphic or sedimentary, so that'd be my first thing, but the two minerals that I think are confused the most often are, it's a mineral called horn blend. It's a type of AMFI. which is black and then a mineral that is called schorl, which is a type of tourmaline.

Jesse Reimink: Ooh, these are, these are tough ones. Uh, yes, these are absolutely tough ones, Chris. good.

Chris Bolhuis: yeah, because they commonly occur in granite. Okay. If you look at a Gran. Granted is mostly light colored. It's gonna be loaded with like shades of gray. That's usually the quarts it's gonna have white, which is usually the Feld spar it'll have often pink or orange or this kind of lightly shaded, mineral. That's another kind of Feld spars in the rock. That's what most of the rock is this light colored stuff. And then it has these like, black dark colored minerals that are kind of peppered throughout it. Right. Usually those minerals are gonna be bioTE, which is super easy to identify. Cause it's this like flaky Micah kind of mineral. Okay. Or it'll be horn blend. This black am bowl, or it'll be schorl. This black tourmaline. Those are like the three. Would you agree with me? It might like, I don't wanna oversimplify. I know. you're gonna object to me cuz you're like, well, Chris, uh

Jesse Reimink: no, this will be the rare occasion where I do not disagree with you. Absolutely. Those are very commonly confused ones and, and difficult to tell apart. I mean, really quite difficult to tell apart, you and I have seen a lot of, both of these in both just rocks that we've seen together, uh, out there in the field and also in mineral collecting locations, like amphibole is very common. It is one of the 10, rock forming minerals. It. Has a lot of iron magnesium. So it's black, it has silica oxygen. It has its Hydris. So it has a little water in its crystal structure, but it's a garbage bag. Mineral, like it has all sorts of different elements in it. And sh this black tourmaline is really very similar. It has the most complicated chemical composition of maybe any of the minerals that any undergrads are asked to memorize the chemical formula for tourmaline is the most complic. And it's really hard to tell the difference. I struggle with it sometimes. Chris. So how do you go about distinguishing the two?

Chris Bolhuis: two things pop to mind. one is like just a visual thing. Right? And then the other thing that pops to mind is, some sort of physical test that you could do to it. Okay. The visual thing is that, schorl this tourmaline

Jesse Reimink: So can I, let me interrupt there, Chris and it's S C H O R L is the, the term for the black tourmaline many people will be familiar with the fancy watermelon tourmaline that people will see in the museums, but this is the black version schorl

Chris Bolhuis: yeah. The visually it often has very prominent vertical situations on the crystal face. And that's the thing that you can like with your hand lens, especially you pull that thing out and man, you just feel warm and fuzzy when you're like, oh, I get to use my hand lens now. And you pull that thing out, you know? And you, you look like a total nerd, but that's okay. but you see these verticals and, = these illustrations are these vertical, they look like scratch. On the crystal face of the mineral, but these scratches are perfectly parallel. They're clearly not a random thing. This is the way the crystal caused these

Jesse Reimink: and they go all the way down the crystal. So they'll, run all the way along the whole crystal, whatever the size of the crystal you're looking. it'll run all the way down. The whole length of

Chris Bolhuis: We say, run down it, cuz sh is this kind of long, skinny pencil shaped crystal. And so they run parallel to the length of the crystal. So that's the easiest way to see it. The other thing is if you're able to do any kind of physical test on it at all, sh is extremely hard and it's harder than quarts. Um, and quarts is extremely hard. So. \ horn blend is quite a bit softer and won't scratch glass. Sure. Get it anywhere near a glass plate and it'll scratch it. So I think to me, anyway, those are the ways to quickly spot the difference in the field.

Jesse Reimink: I there's another one here, Chris, that I tend to rely on quite a bit on this anal versus shore. And it's kind of the mineral associations. Like what else is in the rock? Cause anal is a very common igneous, mineral, meaning it forms in granites. You mentioned granites. It forms in more MEIC rocks, , like GS as well. It'll almost always have bio in the same rock and a lot of bio. So the, the rock that contains an ball will kind of be salt and pepper, or even darker than that. Like the background color. schorl. We just saw schorl. Um, the last day we were in the field, we went to some lithium bearing pegmatites that are 2.6 billion year old lithium bearing pegmatites that some exploration companies are exploring for as a lithium deposit and there's schorl in them, but they don't have biotech in them as FPAR crystals. They have huge quartz, crystals and Chris, you and I have seen this in both Maine and in the black Hills of South Dakota. The huge SHS almost always occur with quartz, PTZ bar, maybe some big books of Muscoy, the, the light colored Mica, but those pegmatites those really fluid, rich things. That

Chris Bolhuis: that's right.

That that's right. And that's the. you gotta emphasize here is that schorl this tourmaline is often associated with pegmatites, which, again, this, we did an episode on this a long time ago. You can go back and look it up, but it's this extremely core screened, , texture in an igneous so that's another thing too. That's a really good point that if you're dealing with a pegmatite, horn blend is not, it's not excluded, but. If you're gonna wage a bet, I would bet it's gonna be tourmaline or schorl in that

Jesse Reimink: that's a great way to phrase it, Chris. And. A really powerful tool for identifying minerals is what else is around it? And you gotta know your rocks and, you know, take some expertise to build this up. But you, if you look at Iraq, you're like, I don't know, is this Shal or Turine look at the other minerals in the rock. And if you can identify the other minerals of rock, you'll be able to really make a very educated guess about, is that schorl or is that, ible

Chris Bolhuis: yeah. Well, and that's right. I think too, it brings up another really important. Like principle in geology is bowens reaction series, which deals with mineral assemblages minerals tend to, only exist with other certain minerals. And so go back to the episode on bowen's reaction series to get a refresher on that and that kind of explanation on why that's the case, cuz there's a definite reason why certain minerals don't exist together in the same

Jesse Reimink: Yeah, absolutely. that's a good set of minerals that are very easy to confuse with one another.

Chris Bolhuis: Did you have another one or are we gonna wrap

Jesse Reimink: Yeah, let's do another one real quick. Just really briefly. I There's two minerals that are really easily confused because they're the same sort of mineral group is that's potassium, Phelps bar and calcium sodium fells bar are called PLA clay. So PLA lace and potassium fells bar, which you alluded to the big pheno crisps, or the big, large grains of potassium fells bar in the long speed granite, that's easy to confuse with PLA clay and. There's no one trick to identifying these things or to distinguishing them. PLA place generally tends to be white, to gray, to dark gray, to like really dark gray on a broken surface. And potassium, Phelps bar tends to be white to pink, like really pink. And so when they're both white, it can be really kind of confusing to distinguish these things. The only really good trick that I. Is look at a weathered surface because PLA place, no matter if it's the really dark, dark, dark gray version, or if it's the sort of lighter gray version, it always weathers to a really chalky white, like brilliant chalky white on the surface potassium, Phelps bar or K Phelps bar doesn't weather that way. It usually weathers to a little bit more. Like the color that you break it. So if you have a rock that you have a broken surface and a weathered surface, you can usually really easily tell if it's lace or potassium fells par, or if it's both, many of them will be both, but that pledge lace always weathers that really chalky white color.

Chris Bolhuis: I'm gonna take that and file away, cuz that is not the answer I would've given.

Jesse Reimink: Oh, what would you have given? That's

Chris Bolhuis: so for beginning geology students, it's good enough just to recognize it and say, oh, that's a Felds bar, but for my geology students, the class you took with me, the upper level class, that's not good enough. You have to distinguish between PLA place and potassium Felds bar. Uh, and so I tell 'em to look at a, cleavage surface of the mineral. Okay, so you have to have a cleavage surface on it and you roll this around, under the light and when light hits that Cleve surface, it flashes off. Right. And what you're looking for are these striations on the Cleve surface. And when you see striations on that, that's PLA place, potassium, felts bar doesn't have that. So that's, that's what I tell my students to do.

Jesse Reimink: that's a really good one, Chris. And the other one that you can use along those same lines is the opposite, when you see potassium Phelps bar, it's divided in half. The cleavage surfaces are divided in half. It's called what's called bite twining. So those big pheno crisps, the big crystals in the long speak granite, they were divided in half in the cleavage surface, meaning one half would flash at you. The other half would not. If it's divided mostly down the middle, that is diagnostic of potassium, felts spa. And that is a for sure, a foot potassium, felts par it's a twinning that only occurs. Whereas the, the striation twinning that you see in PLA place really only occurs in PLA you clay. So that's a, that's a really good one. That's actually more. Diagnostic cuz you don't need the weathered surface to distinguish the two of them. So that's a good one, Chris. Excellent. Excellent one.

Chris Bolhuis: Yeah. stuff.

Jesse Reimink: well that's, I guess that's a wrap, but that's just a brief lead in to. Mineral identification, rock classification. Like this is a huge thing and we'll keep banging our heads against this over the next, six to nine months because, , a lot of people are interested in it. So we'll keep having more little tidbits like that. But I think that's enough to kind of get started as you're out there in the world, walking around, looking at rocks and you see some minerals. This will give you some things to look for. And, uh, some little keys to take note of to help identify mineral.

Chris Bolhuis: you know, we hit a lot of geology today too. So just kind of more like subtle things in geology. I think

Jesse Reimink: And those are they're important, important stuff. So Chris, that's a wrap. Uh, you can visit us on our new website, planet geo cast.com. All the social medias planet geo cast is where we're at and, uh, stay tuned to this space. We've got some more episodes coming out weekly and, , some exciting stuff outside of the episode feed, but you'll get news updates within the episode feed. So stay tuned to that for our upcoming project as well.

Chris Bolhuis: that's right.

Jesse Reimink: Cheer.