How to Identify Rocks
Dr. Jesse Reimink: [00:00:00]
Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
Oh, yikes. You are just funny all the time. you get your funniest stuff out before we hit record.
Chris Bolhuis: Why? What
Dr. Jesse Reimink: I don't know, you're just always.
Chris Bolhuis: a funny guy, Jesse. I'm always on. always on.
Dr. Jesse Reimink: No, you're not always on. You're always on until [00:00:30] you know. What about like 9:30 PM Then you're off, hardcore off, and you are asleep on the couch.
Chris Bolhuis: You know, when I was a kid, I could not wait, uh, like eight year old Chris, right? Could not wait to get older because, then I didn't have to go to bed at nine. I could go to bed whatever time I want. And guess, here I am now I'm old. And guess what I do? I go to bed at nine.
Dr. Jesse Reimink: Oh man, well, we saw each other recently. Right. And I was over at your house. I, I spent, uh, a night or two nights at your house, I think, uh, during this conference and, [00:01:00] We stayed up a little bit later, but it was pretty clear when it was past your bedtime and Chris was getting droopy eyed and Jenny was like, yeah, Chris is tired. He needs to go to bed.
Chris Bolhuis: Yeah, I do. I get droopy eyed, and then when I get droopy eyed, there's very little I can do. I'm, I'm like, I'm, I'm done.
Dr. Jesse Reimink: Yeah. You're basically not entity. It was me and your wife and your daughter hanging out, talking, and Chris is droopy eyed in the corner
Chris Bolhuis: We were sitting in the sunroom, weren't
We Anyway.
Dr. Jesse Reimink: today's episode, Chris, is We could [00:01:30] spend six hours talking about this. We're gonna have to reign each other in, I think, on this topic because it's a deep one and it's basically, inspired by listener question, and many people have this question and we've gotten kind of similar, vaguely similar questions from a lot of people. And the summary is how do you identify rocks? Like what are some key guidelines to identifying rocks when you're not a rock identification expert, right?
You're not a field geologist. You are instead
Chris Bolhuis: is there such a thing?
Dr. Jesse Reimink: As a rock identifying expert. [00:02:00] Well, Chris, just ask me. I think I'm, no, I'm kidding. Um, no, not at all. Uh, but the, the que okay, you're out there going on a hike. You're hiking to, in this case, you know, Richard was talking about old mine sites, or you're just out there hiking along a beautiful path and there's rocks around and there's, you're trying to look at the rocks and understand what they were, you're trying to extract the story of the rocks. Like how do you go about that? This is a really interesting and deep question.
Chris Bolhuis: Yes. So are you asking me how I go about this? Is that what you just did? Did you flip me the
Dr. Jesse Reimink: No, I [00:02:30] don't think so. I'm asking what do you think about the question, I suppose, and then how are we gonna even start to approach it cuz it's such a big topic.
Chris Bolhuis: Yeah. it is a huge topic and it's, it can be really difficult because there are so many nuances in Geology and, rock identification. There.
I try to keep it really simple if you pick something up a rock in the field that is outside of this idealistic system that I'm gonna go through, like, the, what is it, 25 maybe rocks that I have my kids identify in my class, and you [00:03:00] probably have maybe a little less, like you, you probably don't have your students identify that many rocks.
Dr. Jesse Reimink: Yeah, we don't, I mean, we don't have a final exam identification. We don't have a lab final exam like you do. So we basically have a bunch of rocks they identify during labs, but then it's not like a holistic thing that they have to know these 25 or something like that, so they see a lot more, but they don't have to know them all.
Like they have to know it for one
lab session and that's
Chris Bolhuis: Gotcha. Yeah, so my point is that you're gonna pick things up that are outside of that [00:03:30] system, and, you have to just take a piece of it home or take a picture of it, and then when you get back home or you get back to where you, you know, where you come from, then you start looking it up. what's the Geology of the area where you were?
And you're gonna have success then I think finding out exactly what's in your hand. Cuz chances are somebody's done research on this, especially if it's like a mine or a rather well-traveled place.
Dr. Jesse Reimink: Yeah. Uh, so there's a couple ways that my mind goes here and couple things that we could use to structure this [00:04:00] episode. The first is resources. Like what resources should we point people to That can help them start down this path. We should definitely touch on that.
We should talk about like what happens, what do we do, what do you and I do when we come across an unknown rock in the field? Like how do we mentally work through that? And then also talk about what are the things you should know while you're out there? Like We cover the 10 rock forming minerals in Camp Geo, right?
The first link in your show notes, you can go there and learn about these minerals. What are things like that, that people should absolutely know while [00:04:30] they're out there in the field before they take a picture and take a little piece of the rock home if they want? and try and identify, right? Like what are the, does that make sense?
Like there's skill sets, there's the way your mind works, and then there's the resources to use. I, I don't know. What do you think about
that?
Chris Bolhuis: My mind just went in a thousand different directions all at once, right there. There's so much going on in my head. I think great resources. Let's start with that. I think the roadside Geology series are awesome.
because it's so well organized, it, it gives you the [00:05:00] Geology according to where you are in that particular state.
It's organized by states usually, sometimes it's organized by where you are, inside of a very well known national park too. So they're, they're very well organized and then you can, if you pick up a rock, you know that is near a road, then you can look up that road in the roadside GLG series and It's gonna talk to you about that. So I think that's a really good resource. Or Geology underfoot, is another good, [00:05:30] series that's organized in a little bit of a different way, but it's indexable if that makes sense. So you, you know, you can just look stuff up. I think those are two really good resources. And then just Google searching, you know where you are and I found this really weird rock and you will be amazed at what people have put out there.
Dr. Jesse Reimink: Yeah, that, that's a great point. And I think maybe I can summarize the resources you're talking about. location specific resources. And this is a really important point about this. Like you have to know the area you're in, [00:06:00] the general Geology of the path, you're on the park, you're in the, old mine site you're at, like, there are resources online about that. There are probably some books written about that as well that give you, at least a narrow down your list of options, right? When you're looking at a rock, you don't know what it is. Knowing something about the region narrows down your list of potential options for this particular rock you're holding in your hand, right?
Chris Bolhuis: That's right, and I, I think that doing that on the front end of a trip anyway is really, really important because it's gonna allow [00:06:30] you, the more you know about where you're going, is gonna give you a different lens to view that area. Just a little bit of knowledge just. Totally changes your perspective on what you're seeing,
Dr. Jesse Reimink: Yeah. Kristen, you know what, let me
just, let
me interrupt you there. cuz we're gonna have a couple episodes on this exact topic. Like what we do before we're going on a trip, what we look at, what we learn about while you're planning the trip to, to really get the full geological experience of that trip.
So more to come on that front. okay. Maybe let's back up and say, Well, what do you do, [00:07:00] Chris? If you come across, I don't know, if you come across a random rock, and let's say I've handed you a rock and said, what is this Chris? Like, where does your mind go? How do you work through it?
Chris Bolhuis: I think you and I are gonna answer this question about how we do this, I think in really different ways. I'm gonna bring a more simplistic approach. I think, uh, you know, more of a layperson's approach to rock identification than what you're gonna do.
Dr. Jesse Reimink: That's cuz you learned from the textbooks of the 1960s, um, and bef in the pre platonic, prepl [00:07:30] tectonic era, it things were a lot simpler, right. Chris?
Chris Bolhuis: Hey. Yeah, that's right. Yeah. Um, So I think first of all, what you should have with you, helpful when you're gonna identify rocks or, you know, to have a little magnifying lens or a little, geologic little hand lens that you can wear as a necklace. I think a little bottle of acid is helpful and a hammer. Is helpful because when you're gonna identify rocks, you want to have a fresh break on that rock, I can't tell you the number of [00:08:00] times students bring rocks into me that they pick up. It happens weekly or not quite daily, but almost where people are bringing rocks into me and they're like, what is this? And, Some of the times, I don't know because I have no context. First of all, I don't know where it came from. and it's a weathered surface that I'm looking at. So it's got oxidation on it I can't see the minerals that are inside the rock. So I'll ask them, can I break it?
You know, if I can break it open, I can, probably tell you more about what it is. So you really do need to have a fresh [00:08:30] break, and that's the importance of having a hammer.
Dr. Jesse Reimink: I, I think that's a really good point, Chris, and you don't need, so this goes back to our interview with Andrew Alden. Um, About the Geology of Oakland and he brings a rock hammer out or he used to at least, right? He doesn't bash outra. So two things about that. Absolutely. A hammer's a great thing to have.
You don't need a big heavy hammer though, like those little pickax hammers that, we always use es winging, uh, the company es winging, they make great little geological hammers that you just need a little knock a little corner off. But point number two. You have to be [00:09:00] extremely selective. Do not damage valuable outcrops and be very careful about this cuz you know it's easy to, a, hurt yourself and b, damage valuable sites if you're just bashing rocks, you know, on a
whim.
And so be Indiscriminately. Just be very careful that, but I think you're exactly right Chris. This is a Knowing what is alteration or surface weathering and what is internal to the rock is a really, uh, it takes a lot to know that, to work through that. We my wife and I, you know, we have this little Etsy bookshop where we make [00:09:30] bookends and things like that, and the number of times that we, I pick up a rock and I think it's gonna be cool inside.
And she's like, no, no, it looks crappy. It's brown, it's outside. I'm like, well, I know that that's weathering, like I can identify what's weathering and what's not weathering, but that's a really hard skill and it takes a lot of practice to identify that. And sometimes even, I don't know if it's weathering or if it's, you know, if that weathering is gonna be through the rock or if it's not going to be when I cut it open.
Like it's a really difficult question.
Chris Bolhuis: Or when you step into a river and you see a pretty pebble in the bottom of it and you pick [00:10:00] it up, you can't see what's inside of it in that situation. And that's usually what is brought into me. Little small pieces that people pick up from a river, cuz it's cool looking and you really have no idea until you break that thing open.
Um, okay, so here's my generalized approach. to identifying rocks. I have my three things. I got my hammer, and I have my hand lens. So I do it this way. I start with the biggest thing in identifying rocks to [00:10:30] my students. look, they pick it up and the first thing they try to do is name it. And I think that's wrong. I think what you should do is pick up a rock and first classify it. Are you a sedimentary rock? Are you a metamorphic rock or are you an igneous rock? if you can do that, then I think that you're 85% done in identifying that rock. I really, really believe that.
That's something that I've
learned over the years.
Dr. Jesse Reimink: cuz you've narrowed down the list of potential things that, uh, [00:11:00] that can do that. So how do you go about narrowing down that you personally not your students? How do you do it? Like, what do you do to narrow that down?
Chris Bolhuis: So if I pick up a rock, I'm looking around the area too, or what? What do I see? here's my protocol. Are you sedimentary? Are you metamorphic? And then lastly, okay, you're none of those. Then you must be igneous. So let's deal with sedimentary. What do sedimentary rocks look like? Well, if it looks like dirt, tastes like dirt, It's dirt, you know, and it's, we talk about [00:11:30] like sedimentary structures.
you know, does it have any signs of fossils in it? Does it have stratification? Which is just layering in it. is it kind of weaker and softer? so you take a rock and you crack it open, you get a fresh break right now. You take your hand lens out and you try to look at the way the grains are held together.
With that magnifying glass, are they interlocking or are they held together by a, A cementing agent during the lithification of [00:12:00] sedimentary rock formation. by looking at that, like inside the rock now, just the way the grains are kind of stuck together can be really. Helpful in terms of, okay, if they're not interlocking, that's a really good sign that that's a sedimentary rock that you have in
your hand. Does that make sense?
Dr. Jesse Reimink: Yeah. Yeah, absolutely.
Chris Bolhuis: so I do that, and then of course, you know you have your common sedimentary rocks, right? You have conglomerate and brecia, you have your [00:12:30] sandstones, you have shale, and you have limestone and Dole stone. Those are the common sedimentary rocks and I, if you come up with a sedimentary rock that is outside of that, like settle down, take a little piece of it home and learn about what that might be based upon what some, some other source provided information on that area.
Then that's what I would do. So is it sedimentary then? now I can identify the rock. Because now I'm, I'm sifting through a vocabulary that is a much shorter list. [00:13:00] I'm looking through five or six names and there's like a, it's an easy process at that point. If I can get to this rocket sedimentary, I can identify that rock 98% of the time.
Dr. Jesse Reimink: okay Chris, so. So you, you first tackle, is it sediment, right? Are you a sedimentary rock? Then you go to metamorphic. Is that what you said you kind of move to?
are you metamorphic and what's, uh, how do you distinguish between those two? Or like, what are some keys you're looking for in that next, you know, question one B that you're asking the rock.
Chris Bolhuis: Oh, okay. Metamorphic rocks. [00:13:30] Fall into two categories. They're either foliated or they're non foliated, and the foliated metamorphic rocks. That just means that the minerals have an alignment. They have some sort of pattern because they were heated and squeezed, The heat causes the rock to become soft.
The pressure allows the minerals to like reform and align according to that pressure. So I'm looking for some sort of visible pattern in a affiliated rock. And if I see that, and this is not foliation, it's a pattern that's created by pressure, right? [00:14:00] If I see that, I'm like, you're metamorphic. And then the two really common non folated metamorphic rocks are quartzite and marble.
And you kind of need to know the nuances of what quartzite and marble look like. You know, marble is a calcium carbonate, so you can put a drop of acid on it and it'll fizz like limestone. quartzite has this kind of chipping or flaky appearance on a broken surface. it has these little nuances that will help you.
Oh, this is non folated, quartzite or marble. So that's what I do there. [00:14:30] I'm looking for a pattern, or are you quartzite or marble?
And if I'm like, okay, no, you're not sedimentary, you are not metamorphic, then it has to be an igneous rock.
Dr. Jesse Reimink: Okay. And then if you get to that point where it's saying, oh, okay, you're igneous, I know you're igneous. Like, how do you, go into that? I guess, how do you, how do you sort of
Chris Bolhuis: Like, how do I go with, what am I looking for? If it's igneous?
Dr. Jesse Reimink: How do you keep refining if it's an igneous rock? You know what I mean? If you end at
Oh, you're an igneous rock, what's next?
Chris Bolhuis: what color are you? You [00:15:00] know, are you light colored? You know, are you light colored? Are you dark colored or are you intermediate colored? I, I start with that because it's just so easy and that tells us a broad type of chemical composition of that rock.
And then I look at the texture of it. are you a fine-grained? Igneous rock, which means you cooled fast or are you a core grained igneous rock, which means you cooled slowly? Or are you a photic igneous rock, which means you had two different rates of cooling, which is typical [00:15:30] in some volcanic settings.
So that's the way I go through rock identification.
Dr. Jesse Reimink: Yeah. this is an interesting thing because you know, Chris, you and I have, we've identified a lot of rocks together, but it's also been a minute since we've been on one of our camping trips, right? Like, you know, I don't know. It's been a decade, if not more probably since we've actually done this, where we're in a place where neither of us knows what's going on and we're trying to work through this.
I mean, we've done this a lot before, but we've both had a lot of experiences since that time. Right. Like since those [00:16:00] rock collecting days up in Maine or out in the, the
Black Hills.
Chris Bolhuis: it it has been a little bit, yeah. So is my system too simplistic for you then? Like
Dr. Jesse Reimink: No, I don't think it's simplistic. It's different for sure, but I don't think it's too simplistic. I think we, we definitely have slightly different approaches, so I guess it would be fun to, to go collect rocks or go look at rocks that neither of us know again at some point soon here, it'd be fun to work through this, together.
Chris Bolhuis: That's right. That's right. It is. But you know, that doesn't happen very often with you and I because we [00:16:30] do our research on the front end. You know, we, we do a deep dive before we go, so have a really good idea of where we're gonna go and what we're gonna find when we get
there. and that's so helpful. But, alright, tell us about your approach then. Well, like or how would you teach
other people to do it?
Dr. Jesse Reimink: This was a hard one for me. Like when we were, we were sort of prepping for this, I, I sort of thought, okay, how do I do this? Like, it's hard to, to explain your mental thought Process that you go through. so. This is a [00:17:00] guess.
This is what I think I do. I basically, I think the first thing is I have to figure out is this a hard rock to identify or is this something easy? Like, is this something I've seen before or not and you were talking about the weathering on the surface. Like I sort of say, okay, you do that test, first of all this, this rock looks.
Uh, like something I haven't seen necessarily before. Is that just weathering pattern on the surface of if I break it open, is it gonna be Granite? And I know what Granite is, like, is it hard or not? Is it unique or not? Is it a crazy, weird rock? And we've seen some crazy weird rocks at the [00:17:30] various, like old mine tailing piles that we found. We've found weird minerals that you. Rarely find, right? But then there's the common suite of rocks that are like the vast majority of rocks on earth are these 25 rocks that you, you have your students identify, right? So my first thing is like, is it one of the 25 or is it something completely weird and very like regionally focused? So, if I identify it's, it's a rock I've seen before, one of the common ones, and it's sort of a unique take on one of the common ones. I think I worked very similarly through [00:18:00] the process with just slightly different questions. So the, exactly the first thing you said is, is it sedimentary or metamorphic? Or igneous, I kind of say, is it banded or not? Is there fine scale structure to it? Like, is there layering in it and then it's either sedimentary or metamorphic, or if there's not structure to it, then it's either igneous or the affiliated metamorphic rocks. Right.
Um,
Chris Bolhuis: Right. So
you're trying to classify it as well,
Dr. Jesse Reimink: I'm classifying it very similarly, like we're working towards the same goal of igneous metamorphic or
[00:18:30] sedimentary,
but with a different, like starting question, I guess.
Chris Bolhuis: Yeah, let me interrupt you a second cuz when I say are, you're classifying the rock also. Uh, what we mean when we say that is we're, we're not naming the rock, we're classifying it according to sedimentary, metamorphic, or
igneous.
That's the classification.
Dr. Jesse Reimink: If you pick up a rock and you think, oh, I need to like right away determine this is a phite. I mean, you're, you're asking yourself to fail, right? You are definitely going to misidentify this rock.
Like if you're asking that question first, So I agree. You, you kind of start from really [00:19:00] broad scale and then refine on your way down.
Chris Bolhuis: You brought up such a good point right there by mentioning a phool light, okay? That, that falls out of the normal category. Okay? No intro level Geology class is ever gonna talk about a phool light. But when you go to Devil's Tower and you look at the rocks there, it's a Phool light porphyry, but it looks just like a porphyry and a site.
they're both igneous rocks. There are slight little nuances in the chemical composition, [00:19:30] which makes it a phono light and not an endocyte. and so that is not anything that I would ever expect anybody to be able to do in the field.
Dr. Jesse Reimink: Right. I agree completely. This is definitely something that, you know, you take it, you get it igneous and you say, my guess is it's a phytic endocyte, but I'm not sure. You bring it back to the lab and you really nail the mineral identification. And that kind of brings me to my next step, Chris, like I say, is there like structure to it?
And then that allows me to categorize on the left hand side it's sedimentary or metamorphic, and on the [00:20:00] right hand side it's igneous or maybe some of the metamorphic rocks, like it's a rare igneous rock that has centimeter scale layering in it. Right? Whereas almost all sediments have s centimeter scale layering in it, and some
metamorphic rocks have that.
Chris Bolhuis: What are you looking for to classify rock as igneous what sells you?
Dr. Jesse Reimink: Yeah, then it be, so if I say structure not structured, then I go to mineral identification. Can I identify any minerals in this rock? And if it's, you know, loaded with a bunch of feldspar, and [00:20:30] if it has affable in it, it's unlikely to be a metamorphic rock. So there's no structure to it, and it's got a bunch of affable and biotite, it's probably not a metamorphic rock.
Maybe some of the weird ones are, but it's most likely an igneous rock. Whereas on the flip side, if it does have structure and it's got, a bunch of really fine grain stuff and some sand grains in it, then it's probably a sedimentary rock or maybe a little bit of a metamorphos sedimentary rock. Or if there's internal structure and there's garnet in it, it's a metamorphic rock. Like Garnet is not a common sedimentary [00:21:00] mineral. So I kind of go jump right to mineral. Id actually, after. Structure or not structure. Um, and
Chris Bolhuis: Interesting. That is a really interesting approach. That's way different than me.
Dr. Jesse Reimink: Yeah, it is. So I was curious. This would be fun to go, go look at rocks we don't know anything about
together.
Right.
Chris Bolhuis: Yeah. And I wanna say too, that I think one of the best exercises that you can do to kind of like test your knowledge and practice this process is going to a gravel pit. Now, I know of our listeners are like, what the heck is a gravel pit?
I've never, you know,
they're not near [00:21:30] there, but they're all over the place where we're from. Yeah, that's true. Um, gravel pits are really. Awesome place to do this because you have this immense variety of rocks that are there that, that are mostly gonna be rounded, that's why it's in a gravel pit.
And so you gotta break 'em open and you kind of have to work through this protocol. I remember an experience back when I was in college, so this is eons ago,
you
Dr. Jesse Reimink: Yep,
Chris Bolhuis: very, very long time ago,
um, my Petrology professor picked [00:22:00] up It was a nice, okay. And he just, he picked it up.
It was holding his hands and he shoved it toward me and said, Hey, what is this? first of all, I had all this pressure right there that I felt like, oh my gosh, you know, um, he just flat out called me out.
which is one of the easiest rocks to identify. Right. But I kind of froze Then I'm like, I don't know. And he said, it's a nice, and I immediately said, well, how do you know that?
because nobody had ever. Provided me [00:22:30] with a plan for rock identification, which is why this is just something that I've put a lot of thought into. I want to give young people, my students, I want to give them a protocol, you're not just randomly sifting through a bunch of names.
There's a process for this. Classify the rock first. Here are my suggestions on how to do that. Then name the rock.
Dr. Jesse Reimink: Yeah. I agree with that completely, Chris. I think it's a really useful exercise you're listening to this and you [00:23:00] don't know where to start, I think finding people who know a little bit. Doing it with somebody that's really helpful. Like, you know, I learned a lot from you doing this on the various field trips that we went on, I was a very annoying student, right?
Because I would just be
like, well, but okay, may, some people might have considered me annoying, but it'd be like, Hey, I would ask you a question and you'd say, oh, you know, it's, it's this. And I'd sort of say, oh, well why? Like, how do you know that Work me through that. And I've stuck with that mentality all the way through [00:23:30] graduate school.
Like anybody who's out in the field with me and they seem to know a rock that I don't, I'd say, how do you know that? And figure out how they view this process. I mean, some of the best learning ever did was mapping where nobody knows what's going on. In the region and we're actually doing geological mapping and we're, it's just completely unknown.
But I'm with one of the best mappers in all of Canada. So this woman who had mapped for 45 years in the north with a wide variety of rock types, and this was the most amazing learning experience. [00:24:00] Cause I got to understand how she works through this process, right? Like so just soaking that up from other people is the way. to kind of learn from that. And Chris, I think that I, I keep coming back to this, this would be so fun to go and do this again. Like, I, I can't get this outta my head that like, you and I should go do this again cuz it'd be really fun to, to kind of see how we work through it differently than, than we did before. Right. was admittedly young and quite ignorant at that point, and I think we've both seen a lot more rocks and a lot more different rocks since that time. So this would be totally fun to, to kind of do again.
Chris Bolhuis: There is this [00:24:30] pretty common saying in Geology that the best geologist is the person who's seen the most
Dr. Jesse Reimink: Oh yes, I
Chris Bolhuis: You know, there's a lot of validity to that.
Dr. Jesse Reimink: absolutely,
is a lot of validity.
Chris Bolhuis: the other thing that I want to talk about that is a little bit off topic, but you keep saying this. You've said it a number of times, that you were so annoying as a kid. Now I just wanna say that that's not true because What is annoying to me on field trips is when I'm treated like a tour guide.
when students or people treat me that way, I don't [00:25:00] like that at all. That's annoying to me. I love curiosity. I'm a curious guy. I want to know things, okay? And I love it. Then when students have that curiosity, cuz that means they want to know, they're curious about it, they are passionate about it, and so, I am the other way.
If I have to sit down a group of like students in the field and say, listen, you guys are boring the heck outta me. You, you know, that means they're not asking questions. You
Dr. Jesse Reimink: that's true. That's that.
that's a good point. That's a good point. Yeah. I, [00:25:30] I, feel the same way. There's nothing worse than a bunch of students who say, oh, here's the rocks. You know, go identify them. And they just kind of wander around aimlessly picking it up, writing things down, and don't really ask any questions.
And the best students are. In my experience, not the ones who get the A's, they're the ones who pick up a rock and are like, whoa, I don't know what this is. This is so cool. I gotta figure, I gotta learn how to figure this out. Who are kind of like really interested in working through it. And they don't always get the best grades.
That's completely fine. Like I, that's the
Chris Bolhuis: I, I agree. A [00:26:00] hundred percent. look, when you take a group of young people to the Tetons and you, you know, you have all this Geology in front of you and you, you begin to talk through the Geology of it. How can they not have any questions about what's in front of 'em? If they don't have any questions, then something's wrong.
and so, no, I, I, yeah, you need to stop saying that cuz you weren't annoying. You were actually the opposite. That's the first time that I actually saw your personality. I. know, like,
Dr. Jesse Reimink: Is we're getting excited about rocks.
Chris Bolhuis: yeah. It was,
Dr. Jesse Reimink: [00:26:30] So, so Chris, I just want to come back to this like first definition. The, the first thing that I go through is like, is it a normal rock or a weird rock? Right? There's a lot of rocks that are very normal, that look weird initially, and it's either weathering patterns or it's something that makes it look like gold or look like, some really weird, really
cool thing.
Whether it's shiny mica that has had some,
uh, oxidation to it, right, that is flaky and, and is shiny. [00:27:00] People look at it and it, it is a beautiful mineral. Like there's. There's no doubt this is a beautiful mineral and it makes beautiful rocks, but it's also one of the most common minerals out there. Right.
and it occurs everywhere. And so it's important to identify that and also important to recognize that this is not a crazy, unique rock. And I think, you probably get this a lot too, but I get emails from people being, you know, Searchable on Penn State's website as a Geology professor.
You get emails that are like, what's this rock? And actually the first question I ask myself is, is this a rock or not? Is this slag, [00:27:30] is this some weird concrete thing that they found in their backyard, right? Like, is this actually
a rock or not? Is really one of the first questions.
Chris Bolhuis: That is such a good point. It happens all the time where people bring in a piece of concrete, and concrete can be beautiful
actually. Um, it it's, it's. Yes, because it's loaded with real rocks and real minerals that are just kind of held together by, you know, by cement.
So it can, that happens all the time.
Dr. Jesse Reimink: I remember Chris when I was, I think I [00:28:00] was after college or something, there was, uh, one of your colleagues who thought it was quite good fun to sneak concrete into your rock garden and see how long it would take you to find it out, to figure out what that somebody had snuck a big chunk of concrete in there.
That was, we, I always got a kick out of that prank. That was a pretty
Chris Bolhuis: He would always come into class too. He, he thought it was really funny. He'd come in with a, a handful of gravel and he'd come into my room and interrupt me. Um, you know, I'm hitting my mid stride right? And he interrupts me. He's like, Hey, can you please identify these rocks? and then he [00:28:30] would just
laugh endlessly. So yeah.
Dr. Jesse Reimink: Alright, so Chris, I wanna wrap up this episode maybe with just like, It's hard for people to know how to get started, and it's hard when you're walking out there with zero knowledge. Let's say. apart from listening to some episodes of a podcast,
what are the key things you should learn or, or think about before you go out into the field and identify rocks, like what do you need to kind of get started on this? Is it sedimentary, igneous, or metamorphic process? Because there's a little bit of a, a learning curve before you can do that.
Right. And how would
you,
Chris Bolhuis: Yeah, good [00:29:00] question. Really good question. I think two things jumped to my mind. One is Get yourself familiar with the common sedimentary, the common metamorphic, and the common igneous rocks.
And we have these laid out beautifully, I think beautifully tooting our own horn, but in Camp Geo. So if you go to that, we have chapters that are devoted to the common types of all of these rocks with images that you need. It's just a really good way to familiarize yourself with that, I think.
So that's the first thing that jumps to mind is get [00:29:30] familiar with them. The second thing is, do your research before you go.
Dr. Jesse Reimink: Totally. I think I would, agree completely with both those things. I would slightly amend and say rocks and minerals and you know, learning the common minerals will help you as well. And you don't really have to like know the difference between quartz and feldspar, but you kind of have to know, I see something and it, it looks like quartz or sbar. You can kind of put those in the same bin, but knowing the 10 minerals, and again, in Camp Geo we cover that. There's a lot of really good websites out there that have a bunch of images of different minerals as [00:30:00] well. It's a little bit hard to do without the rocks in your hand.
but you can go to a little gem min or mineral museum. Like most universities will have a little gem and mineral display. Penn State has this, it's open to the public, like, go there, look at these things and just. Learn as much as you can from books or websites. And again, point us to Camp Geo.
That's a really, we've done a good job of that. I think, even though it's not catered to mineral and rock identification, it is the intro Geology course. And so you get that information along with it, [00:30:30] right? Like learning how to
identify as these things is a key part of a geoscience education.
Chris Bolhuis: The only other thing I would add is settle down. If you can't identify the rock, relax. It doesn't mean that you don't know anything. there are many, uh, an accomplished geologists that are out in the field that cannot identify the rock until they get it back in lab,
Dr. Jesse Reimink: Oh, you know what? There the number of times I have thought Iraq is one thing out in the field and then bring it back and it's something completely different. I mean that it happens often than I would like to admit, but actually it happens to all the best field mappers. [00:31:00] Too, and it, I think the key thing is just be honest about that.
Like, I don't know what this mineral is and I'm gonna need to do some homework to figure out what it is. And a lot of that homework you've pointed out, like learn the regional Geology, learn about the specific site. and sometimes you'll find some weird stuff, but it's pretty rare to find a really, really totally unique thing that, no one's known about or documented in that location before.
there are geologists who've been there before and have written something about it. cool, man. Well, that's a big episode and a lot of stuff to, to work through, but
Chris Bolhuis: Yeah,
Dr. Jesse Reimink: we did a [00:31:30] decent intro job right.
Chris Bolhuis: I, I hope so. It only took us three years to get to this episode, so
Dr. Jesse Reimink: Yeah. And on that note, if you have questions, if you're listening to this and you have questions, you want, uh, sort of more information, or you're learning this for the first time and, and you have some questions, you know, rock ID is always hard to do over in. over an image sent to an email. But if you have questions about the strategy or the differences between major rock types, Hit us up. We are planet geo cast gmail.com. All our social medias are at Planet Geo Cast. Go to our website, planet geo cast.com. There [00:32:00] you can subscribe. Support us. We always love that. And you can leave us a rating and a review on your podcast platform.
We always appreciate those
Chris Bolhuis: Yeah. Thanks Richard for the question.
Dr. Jesse Reimink: great questions, Richard.
Chris Bolhuis: Cheers.
Dr. Jesse Reimink: Peace.
