(guitar music) – [Voiceover] Some of
our most valuable gems and rare minerals
are found concealed in bands of pegmatite rock. How do these rocks
produce the minerals we use for everything
from jewelry to the batteries
for our cellphones? Scientists are
studying pegmatites and their incredible crystals to unlock their mysteries. Join us now for a conversation with geologist Mike Wise. To dig deeper into the science of nature’s crystal factories. Now here’s your
host, Maggy Benson. – Hi. Welcome everyone! Thanks for joining us
for another episode of Live from Q?rius:
Smithsonian Science How. We’re so happy to have
you hear with us today. We’re also really excited to
welcome our special guest, geologist from the
Smithsonian’s National Museum of Natural History,
Dr. Mike Wise. Hi, Mike. Thanks for
joining us today. – Hi, Maggy. Thanks
for having me here. – So, Mike, you’re a geologist here at the Smithsonian. – Yep. – Can you tell us what you do? – A lot of different things. I study rocks and
minerals, primarily. In the lab and in the field. And when I’m not doing that I also have duties helping to build our collection of
rocks, minerals, and gems. And I also do some
education outreach here at the museum and
also out visiting schools. – [Maggy] Very cool. So, what made you get
interested in geology as a field to make
it your career? – I got into geology by
accident. As a young boy, I was always
interested in science. Whether it be astronomy, or biology or chemistry. But where I grew up, there were no rocks. So, I didn’t really have a
rock and mineral collection like a lot of
geologists may have had when they were younger. And I really didn’t
get into geology until I went to college
at University of Virginia as an undergraduate and I took a couple of courses and got exposed to geology and I found out that
I really enjoyed it. – So, Mike, here at the
Smithsonian as a geologist, you study one very
special kind of rock. What is that? – I study a rock
called pegmatite. It’s a type of igneous rock that’s pretty unique, I think. – [Maggy] What is igneous rock? – Igneous rocks are rocks that form from crystallization or solidification
of molten magma, or melted rock. Whether it be below the surface or erupted at the
top like volcanoes. – So, is that something similar to something like granite, that I’m familiar with
as an igneous rock? – Yeah, actually, in fact, pegmatites have mineralogy
very similar to granite. Typically, granite is
made up of feldspar, quartz, and maybe some micas and pegmatites as well. I have some examples here. This is a mineral, feldspar. We have an example of quartz and a big sheet of mica. So, it’s basically
the same minerals as most granites. – [Maggy] But what’s different? – What’s different
is the grain size, the crystal sizes. If you look at a
typical granite, most of the crystals
are really small, about a millimeter or so. But pegmatites can grow
these giant crystals. I mean, giant! Bigger than you, bigger than me, and I’m six foot three. (Maggy laughs) Some of the largest
crystals ever reported came from pegmatites and they’re about
fifty feet long. So, think about the size
of a telephone pole, to give you an example. – [Maggy] That’s huge. So, what we’re looking at here. I mean, this mica that
you just showed us, is gigantic. – Gigantic for
most igneous rocks. If you look at volcanic rocks or any other type
of igneous rocks, they don’t form crystals
that are very large. Only pegmatites do. – So, what makes
pegmatites unique in their formation? – Well, they’re unique
in their formation in that they are
able to concentrate a lot of rare elements. A lot of elements
that don’t occur in large quantities
in most igneous rocks. So, for example, you
have elements like tantalum and
beryllium and lithium which make occur in
those pegmatites, but in the formation
of a granite body, the style salt is a granite
melt below the surface – [Maggy] So, that’s
volcanic material. – [Mike] Well, it’s not
really volcanic material. It’s molten rock. We only consider it
volcanic material when it erupts at the surface. but as the granite
is crystallizing the elements like
tantalum and lithium don’t go into the
mineral structure of the feldspars and micas. So, they remain behind and end up in this
water-rich solution that eventually squirts
out into the country rock and those eventually
crystallize to form pegmatites. – Wow. Very cool. So, I see a huge diversity
of shapes and colors in the huge crystals that
are here on the table. What causes this diversity? – The diversity is
due in large part to the chemistry. It’s a very unique chemistry as far as most igneous rocks go. Pegmatites, whatever
that process is that makes pegmatites allows them to concentrate a lot of unique elements. Almost half the
periodic table, in fact. – [Maggy] Wow. – [Mike] Yeah. So, most
igneous rocks don’t do that. And these concentrations
can be very, very high. – So, you said that these
minerals are made up of elements and sometimes rare elements. Do you have an example
of a rare element here from a pegmatite? – Yeah. We have this
mineral called tantalite. It’s extremely rare and it’s
only found in pegmatites. One of the major
elements in this mineral is an element called tantalum. Now, tantalum is
important because it is useful in the
making of electronics. And If you look at the
abundances of tantalum, in the earth crust. You’ll see that it’s
about one part per million and if you look at the
tantalum concentration of a typical granite,
it’s about two. So, that’s still pretty low, but typical for
most igneous rocks. The pegmatites and
tantalites can have up to 300 to over 750 thousand
parts per million, tantalum. So, that’s a lot of tantalum. – So, basically
you’re being able to get a crystal large enough with enough tantalum in it to actually use that tantalum. – Right. So for most
rocks where tantalum would be considered rare. Pegmatites, not so rare. – And you said that
pegmatites are able to concentrate many
different elements. – Yep. – Is this rare for other rocks? Is this unique to pegmatites or does this happen
in other rocks, too? Well, in other rocks may
have those same elements, but only in very
small quantities. And there are some pegmatites that also have
these rare elements, but in small quantities. But in special pegmatites, like some of the
examples I have here, yeah, you can get
large quantities of tantalum, beryllium,
lithium and other rare metals. – Very cool. So, Mike, just in this
brief amount of time, you’ve taught us that pegmatites have this ability to concentrate lots of different
types of elements into very large crystals that can then be used
for other things. I wonder what the most
important property is, though, about pegmatites. Should we ask our viewers? – Yeah, let’s find
out what they think. – All right, viewers,
here’s your opportunity to participate in a
live poll with us. You can respond using
the window that appears to the right of
your video screen. Tell us what you think. Take a moment to think about it and put your answer in
the window to the right. (lively music) – So, Mike, the
results are coming in and we really have a
pretty even distribution between large
crystals of minerals and minerals valuable
for human uses. The poll’s still changing, but what do you think? – Well, all of those
are pretty good answers, but I think the most
important feature is the large crystals because, frankly, that’s
what defines a pegmatite, is by the large crystals. So, for me that’s the
most important feature. – And what makes large
crystals so special? – Well, large
crystals enable you to make very large gemstones, really super nice
mineral specimens and it just makes
pegmatites fun to study. – [Maggy] And really beautiful. – Yeah, really beautiful.
(Maggy laughs) – All right, Mike, we have a
student question. You ready to take it? – [Mike] Okay. Fire away. – All right. Let’s see. – Hi. I’m Ella and
I’m a fifth grader at Floris Elementary School. My question is what do pegmatites
tell scientists about the region’s history? – Wow. That’s a
really good question. Sometimes pegmatites can
tell you a little bit about the geology, the local geology
that’s present, but sometimes they don’t. Sometimes pegmatites
occur in rocks that have nothing to do
with the geology around you. And in other cases, they’re related to
the granite bodies that probably formed them. – [Maggy] Great question, Ella. – Yeah, that was a good one. – So, we have
another question here, and this one comes
from the MSNV school. How many pegmatites
have you found? (Mike laughs) – How many have I found? Wow, that’s a hard one. I can’t say that I’ve found
some new ones, myself. And I visit a lot of
places around the country, but there are some pegmatites that I have looked at that have never
been studied before or have been
studied in detail. So, I don’t think I
can really answer that, how many new ones I’ve found. (Maggy laughs) – All right. We have
another student question. This one comes from Sahaj. Do you only study gemstones? – No, I don’t only
study gemstones. In fact, I also study
minerals from pegmatites that are pretty black and ugly and most people probably
wouldn’t even pick them up in the first place. But even those minerals can give us some information about how pegmatites form. – Wonderful. Great questions. Keep them coming. – Yeah. That was a good one. That was a real good one. – So, Mike, I wanna
learn more about the human uses of pegmatites. What kind of economic value
does this type of rock have? Well, unlike a lot of
other igneous rocks or other rocks, in general, pegmatites have basically four
different types of material that they can produce. There are things we
call strategic metals, industrial minerals,
gemstones, and collectibles. – So, let’s explore
each one of those now. And let’s start with
strategic metals. What does that mean? – Well, these are metals that are required and used
in industry and technology and in the military field. – [Maggy] What kind of
pegmatites are used? – Well, it’s not so much
the pegmatites themselves, it’s the minerals
that are present. So, for example,
tantalum, tantalite. Tantalum is really important
in the use of electronics and today’s technology. So, without tantalum, a lot of the things that we use or take from granted
don’t work properly. So, for example, your
cellphone and smartphones have this little device
called a capacitor and in this particular one, which we ripped the back off, there’s this little,
tiny, square thing here called a capacitor which
stores electrical energy that the cellphone can then use. And so, pretty much
every electronic device like cellphones, computers,
video game consoles can have capacitors in them. – [Maggy] So, what happens
if there wasn’t tantalum? – They might not work. (Maggy laughs) In fact, there was
several years ago, when the PlayStation 2 came out, video game came out, there was a shortage because
of a shortage of tantalum. There wasn’t enough tantalum
to make all the capacitors needed to fuel their orders
for these PlayStation 2s. – Wow, interesting. So, tantalum and pegmatites
are incredibly important for our gadgets to work. – Yep. There’s also an
element called lithium, and lithium is used to
make lithium batteries which we all know are in
the cellphones as well. – [Maggy] And what kind of
pegmatite does that come from? – It can actually in a same
pegmatite that has tantalite. So, it comes from the
mineral, spodumene, which is the primary
ore for lithium. – Very cool. So, let’s explore another one of those human uses. You said that they’re
used in industry. What kind of industry? – Well, the industrial minerals
are basically nonmetals. So, things like quartz
and feldspar and micas, which are not really
metallic minerals, those are used or
mined from pegmatites for use in the
glass-making industry in making cookware
like Corningware, things like that. The micas are used in
paints and in cosmetics like makeup, eye shadow.
– [Maggy] Oh! – Yeah! – [Maggy] I have to
think pegmatite minerals for makeup today. – Yeah. It’s what
makes it glitter. (Maggy laughs) All that glitter is due to little tiny pieces of mica that’s ground up and incorporated
into the cosmetics. – Wow, Mike, so, who
knew that everything from makeup to cellphones
to gaming consoles depend on the minerals that
are produced by pegmatites? – Yep. That’s right. – So, there’s another one,
another use that you mentioned gemstones and I see some
beautiful stones here. – Yes. We have a
few gemstones here. And this is what most
people may be familiar with, things like aquamarine and topaz and tourmaline and garnet, they’re found as gemstones that are cut from
minerals from pegmatites. – Now, some of them, I would hate to actually cut up. Is there a use for
some of these minerals in this raw form? – [Mike] Well, I hate
cutting them up, too. But before I get on to that, I have something I want
to share with our viewers. – [Maggy] All right. – In order to cut…
– [Maggy] What can it be? gemstones. – Wow! – This is a cut stone of quartz. (Maggy laughs) You’re speechless. – I’m totally speechless. I could never wear
that in a necklace. – No, I couldn’t either. (Maggy laughs) And you wouldn’t try. But think about this. In order to cut a
gemstone this big, you gotta have a big crystal. This is just simple quartz and this particular
specimen is from Brazil. It’s almost 20,000 carats. – 20,000 carats! – Yep. And it’s
from a pegmatite. – That is so incredible. – Well, the crystal
is from a pegmatite. – So, this huge gemstone, the actual crystal
that it came from must’ve been… – … had to be big. It had to be at least
twice that size, at least. – Wow, that’s amazing. – Yep. – So, let’s talk about
the actual crystal that it came from, their value. Is there a value for those? – Well, actually, they are. Just like people collect stamps and collect coins,
you know, model cars, whatever the case may be, there are people who
collect minerals, as a hobby. And this has been going
on for many, many decades. And even today, they still
collect pegmatite minerals because they’re beautiful. – [Maggy] They really are. I’m truly speechless. These are just… It’s just an amazing
array of materials. (Mike chuckles) – So, Mike, are these actually in the museum’s collection? – Actually, pretty
much all of these are, there are a few things
that I collected doing my research, but hopefully they’ll get
into the museum collection when I’m done with them. (Maggy chuckles) And so, you can see, people
can come to the museum and they can see
things like this in our geology, gem,
and minerals gallery which has a whole section
just devoted to pegmatites. – Very cool. So, Mike, I’m ready to go out and
start mining these myself. But… – Mining, yes. (Maggy laughs)
Sure. Digging, looking for
pegmatites myself. We have a student
video question, though. So, let’s go to that. – My name is James. And my name is Collin. We are fifth graders at
Floris Elementary School and our question is where do you find most
of your pegmatites? – Great question, guys. – Mike, I think
that’s a question that we should actually
ask our viewers. – Yeah, let’s do that. – We’re all ready to
search for pegmatites. Here’s another opportunity to
answer a live poll with us. Tell us. Take a moment to think about it and put your answer
in the window to the right of
your video screen. (lively music) Mike, the results
are still coming in, but 85% of the viewers
think that answer is b, mountains. How’d they do? – All right. That’s good because most granites, most of the pegmatites
associated with those occur in mountain ranges. – So, can you give us an example of some pegmatites that
you’ve actually found in your career here? – Yeah, when I
first started here, I actually was spending
most of my time in Maine looking at pegmatites there. Then I started working
in Rhode Island and then Virginia,
North Carolina, and then as far
west as California, – So, I know that you
found an amazing specimen in Colorado. Can you tell us about that? – Yeah, during one of
my trips out there, one of the miners had
found some pegmatites and he found these pockets which are essentially
holes in the pegmatites where crystals can grow into. And he invited me
to stick my hand in and see if I could
pull something out and I did. I reached in, felt something
that felt like quartz crystals, wriggled it out, pulled it out, and pulled out a very
nice amazonite specimen which is green feldspar
with black smokey quartz. – [Maggy] So, this is
what we’re seeing here? – [Mike] Yeah, that’s the piece. And the nicknamed it
the Smithsonian pocket because I was a Smithsonian
employee at the time, but the sad thing is we didn’t get to keep
this for the museum. – It’s really a
spectacular sample. – Yeah. It was fun. – I mean, being the
first to pull something out of the ground
for the first time. – So, Mike, are pegmatites
located all over the world? – Yep. They are located
on every continent. Even Antarctica. With all that ice, you never would expect
that there are rocks there, but there are some
rocks exposed. And there are pegmatites in some of the mountain
ranges in Antarctica. – [Maggy] So, if I wanted
to go search for pegmatites like the minerals
that this one produced would I know were to look? Do scientists know where certain pegmatite
minerals are found? – [Mike] We have a
pretty good understanding of where the major
pegmatite deposits are, the major pegmatite areas, like there’s so many. Brazil is one of them, in fact. But one of the things that
I’m trying to understand is, is there a connection
between the type of pegmatite and broad geologic processes? So, for example, we
know there are places where the earth’s
crust comes together to form mountain chains like the Himalayan Mountains or the Appalachian Mountains. There are large
amount of granites where they develop and there are pegmatites strewn all along
those mountain chains. Whether we can determine if there’s a specific
type of pegmatite in those mountain chains, that’s one of the things
we’re trying to understand a little bit better. – So, as a scientist
here at the Smithsonian, you’re actually looking
at the internal structures of these crystals and trying to better
understand their chemistry. What kind of techniques
do you use to do that? – A lot of different techniques. If I find a mineral that
I don’t know what it is, the first thing I’ll do is
use a X-ray defraction machine which actually gives
us an idea about the atomic arrangement of
that particular mineral, which is essentially
a fingerprint. Every mineral gives off
a specific X-ray pattern. From there, I’ll move on to
the electron microprobe which gives us
chemical information. So, it allows me to determine which elements make up
that particular mineral. And then we have a scanning
electron microscope which is basically
used for imaging. Although, we can get some
chemical information. And it allows us to
see surface features or if we have a polysection, we can see things like zoning or if there’s
replacement going on. All bunch of really neat things, you couldn’t see
with the naked eye. – But you said earlier, that you can see some
things with the naked eye like such as color
indicates chemistry. Do you have an example
to show us here? – Yes. I brought
with me a specimen. It’s a slice of a mineral
called liddicoatite. It is a type of tourmaline and one of the neat things
about this particular sample is that you can
see various colors. – [Maggy] It’s beautiful. I see a pink triangle
right in the middle. – [Mike] Yeah, there’s
a pink triangle there and then there’s green bands. And we know from
studying tourmalines that the green color is
due to the presence of iron and the pink color is
due to the presence of the element manganese and so, just by looking at this, we can, much like
the rings of a tree, we’re looking at
the growth history of this particular tourmaline. – Wow, that’s fabulous. Do you have any other examples of how you can sometimes use techniques such as light
to better understand? – Yeah, I have an example of what’s called opal. And it’s not like the opals that most people see
in jewelry, okay? But it’s still opal, nonetheless because it has the chemical
composition of opal which is silicon, oxygen,
and a little water. But one of the neat
things that happens when you subject this
to ultraviolet light is that it changes colors. So, we can dim the lights just a little.
– [Maggy] can I see it? – [Mike] Sure. – [Maggy] Yeah,
let’s dim the lights. Oh, how cool! It’s
actually glowing. – [Mike] It’s actually glowing. So, we don’t really
know what causes this not all opals do this, but this particular type of opal may have little bits of uranium. I mean, really,
really, tiny amounts that causes it to
react with the energy from the ultraviolet light and cause it to glow. – [Maggy] And do all
opals glow like that? – No, they all don’t. Most opals, again, that you use
in jewelry will not do this. This is not a property
of those types, but I’ve looked at a few
opals from pegmatites and almost all of them do. – Wow, that’s
really fascinating. So, Mike, you’ve taught
us a lot about pegmatites, their amazing diversity, and how you’re studying them. So, thank you for that. I think we should go to
some student questions. What do you say? – Okay. Let’s go. – All right. So, this question
comes from the Auburn school, “What temperature and
depth do emeralds form?” – Wow, emeralds? (joyful laughter) – Are emeralds part of
the pegmatite family? – Well, sometimes they can be. They don’t always grow
right in the pegmatites, but to form emerald, you
need two things to happen, you need a source of chromium, that’s what gives
it the green color. – An element. – An element. You need
the element beryllium which, in most cases,
comes from pegmatites. And so, you typically find them on the edges of pegmatites, if that pegmatite intrudes
the right type of rock. And so, the temperature
of formation could be 500, 400 degrees Celsius. And we may talk about, 5, 6
kilobars of pressure. Something in that range. – [Maggy] So, a lot of pressure? – A lot of pressure and
a very high temperature. – Very cool. We have another question.
– [Mike] Great question. – And this question comes
from Mr. Holmes’ class. They wanna know, “Are certain types
of pegmatites, more – Good question. And the answer is
definitely yes. In fact, if you took a survey of all the pegmatites
in the world, if we could, and we would come up
with such a large number, well over 100,000 pegmatites, probably 99% of those are
very simple mineralogy. Just quartz, feldspar, and mica. – [Maggy] So, just like granite? – Just like granite. Less than one percent of them have all these
really cool minerals that we’ve shown here. – So, we have another question. This one comes from
Meg and Charlotte. “What is your favorite
pegmatite specimen “at the Smithsonian and why?” (Mike chuckles) – Meg. Everybody asks
me that question. I have a hard time
picking a favorite because I like them all. Whether they’re really
gem quality ones or just this cruddy, black,
little skin on the surface. I do have a favorite
pegmatite gem, though, that’s called a tourmaline. It’s a Paraiba tourmaline which has a very unique color. It’s the color of Windex. So, it’s this Windex blue color. It gets this color
from the presence of copper in the tourmaline which is quite uncommon
for tourmaline, in general, to have copper. – Very cool. We’ll have to
find some Paraiba tourmaline. – Yeah. If you want to
find Paraiba tourmaline, you gotta go to Brazil
or Nigeria or Mozambique. – I have to add it to my list. – Well, I’m ready. Let’s go. (Maggy laughs) – Okay. This one
comes from Julia. “Have you ever discovered
a new mineral?” – Funny you should ask, Julia. I haven’t discovered one yet, but I’m working on a couple. One of them is from the
pegmatite down in Virginia, the Norfolk pegmatite. A few years ago, a collector sent me
some material to look at and it turns out it’s
not like any mineral that we know of at this point. So, I’m actually still doing
some of the chemical work, some of the X-ray work, and hopefully, it will
become a new mineral species. – [Maggy] We have
one last question. And this one comes
from MSNV school. “Have you ever looked
for pegmatites in Maine, “If so, what have you found?” – Probably the best
question of the day. (Maggy laughs) Only because that’s where
I started my research here when I started working
for the Smithsonian. I spent a lot of time, a lot of years, looking at the
pegmatites in Maine. Primarily, the pegmatites in
the western part of the state, close to the New
Hampshire border, and I found all
kinds of minerals. In fact, this tantalite
specimen I brought with me, it’s from Maine. – [Maggy] Wow! – It’s from what’s
called the Hayes Quarry. And I had to fight off
one of my colleagues to bring it back because
he wanted to take it. But I found tantalite, we found beryls, spodumene. – Oh, I know I’m very interested
in looking for pegmatites. And maybe some of
our viewers are, too, in Maine and in Virginia. How can students get involved, if they’re interested
to learn more? – Well, if you want to
learn more about geology, I would suggest go outside. Go look at a rock. Pick it up, study
it, break it open, see what’s in it
because frankly, rocks gives us the
clues to understanding how the Earth works and this is what geologists do. We look at rocks. If you don’t have
rocks in your area, like I didn’t have any
when I was growing up, go visit your local museum. Look at the geology
collection or display. If you’re in D.C., visit
the Smithsonian here, visit the Natural
History Museum, and stop by the geology,
gems, and mineral gallery. And if you have
time after all that, you can stop by Q?rius, you could actually
pick up specimens, look at them under a microscope, handle them, much like – Like this? – Yeah. much like a
geologist would do. – Thank you so much, Mike, for helping us understand
what pegmatites are and how cool they really can be. – Thanks for having me. And thanks for all
the great questions. I hope you’ve got some young
pegmatologists out there, in the future. – Me, too! Thank you so much for joining
us for this episode of Smithsonian Science How. If you want to see
the program again, it’ll be archived later
this evening on qrius.si.edu (guitar music) – [Voiceover]
Thanks for watching. You can explore more
Smithsonian Science How shows and teaching resources
on our website. (guitar music)