Hello and welcome back for another
presentation this one on your
introduction
to minerals. So this is going to be a a
presentation system that's going to
build off of each other be broken into
two parts.
First part minerals and then we'll move
forward after that into
introduction to rocks but before we can
get to rocks
We have to understand the foundation and
building blocks of minerals.
So let's get going, so again we're gonna
be starting off with an introduction to
minerals
So what is a mineral?  Well there's a
couple
attributes to the definition
of what a mineral is. So we're going to
work through that
and then we'll learn how to identify
things that are or may not be
actual minerals. So the first part is
minerals are made
up of at least one or more element
So take yourself back to when you take a
chemistry class or you took
some science course and had the periodic
table of elements
Well those are really the building
blocks of minerals
So minerals are made out of one or more
element that can create a compound
the next part of that definition is
minerals are defined as being
naturally occurring. Which means they
must come from nature
they're not human-made, the second part
is they must be
inorganic. Meaning it could not have
grown from a plant
The next part of that is that they must
be well defined with their chemical
composition and an ordered atomic arrangement
meaning a crystalline. So what does that mean? Well that last
part in specific
means that minerals have a very distinct
recipe that make it what it is.
So that being said as an example, quartz
quartz is a very common mineral
but there's different variations there's
yellow quartz,
there's white quart,  there's gray quartz
there's a pink and a purple.
So all of those have very distinct
recipes okay. So just think about it it's like we
have a cake but we have different
variations
of that cake but we know specifically
what part of that recipe needs to change
in order to make it
a little bit different. Another thing
since i've mentioned it, inorganic means
that it cannot come
from plants. So perhaps you've been to
places where they sell rock candy or
they sell the crystal sugar cubes on a stick and
they say that this is a mineral.
It's not a mineral right because we know
that sugar is glucose which comes
from plants. So when you're buying a lot
of your drinks your fancy drinks and
stuff like that and your energy stuff
and it says it's full of minerals it's
probably meaning that it's got potassium
and salt which are both genuine minerals
but everything else is chemically made
it's made by humans or it's made by a
plant
So it doesn't really count as having a
mineral in it
So moving forward minerals also have
physical properties
such as color, luster, hardness,
streak and cleavage or fracture. We will
be spending some time going through each
one of those
but those are really just observational
features. So what are the
what is the actual color of that
specimen? Luster is really how does it
reflect light so is it dull or is it
metallicy or is it glassy
we can look at the hardness physically
how hard is that specimen?
streak is the color left behind when you
scratch it on a tile
and then how does it break?  Does it break
into a pattern or does it just shatter
like glass
that'll be cleavage versus fracture
that being said the international
mineralogical association has recognized
nearly 5500 different minerals. Again many of these
are variations of the same.
Again like i use that you know that
analogy with a cake. We have cake but it's a strawberry, vanilla, cherry, raspberry, poisinberry
and what is the variation of that? So
they're all individually different
but yet it's part of that same grouping
So i hope that helps, moving forward
we'll move into the story of a mineral
So where does it begin? Well it begins
with the story of
atoms and elements and then they are
able to come together
into a proper proportion meaning a
recipe
So often in geology courses you'll learn
looking at the chemical bonds and it's
really it's like those, you probably have
seen them they're little wooden balls
that have
metal brackets between them and to show
the chemical composition the compound
of that foundation that's where this
begins. Things that take into consideration
time, temperature and space. You need to have an actual time
allotment for these and usually one point molten materials
to then
come together and then you need that
time for it to cool down to crystallize. You also need the time for the
temperature
and you also need the actual physical
space. We find that many crystalline
structures
can be constricted based on the space
whether it be small
or large. An example of that would be
like looking at a geode, a geode or those
rocks you cut in half
and inside have a mineral crystalline
structure. Sometimes if it has too much time and
not enough space, that geode will just fill completely
with crystals where there's really no
nice design
it's called a thunder egg because it's
solid. Or maybe you have very small
crystals because it cooled very quickly
and had lots of space you've got lots of
little crystals inside. That being said the last part here is as
atoms keep being added in this array or style
Repeating that basic arrangement the
creation of crystals becomes bigger
and the development becomes more clear. So versus having a very small crystal
versus seeing very large ones. You know how much time was allotted for
that to occur. We find that especially in the
development and crystallization of
minerals
that the longer you have in time
the larger the crystals will be present
or observed. All right so moving forward
let's start talking about some of these
physical properties
So I brought forth these you know two
slides ago
color, luster, hardness, streak, cleavage or
fracture
So we'll talk about these here and then
I actually have a slide for
for each one that we'll be able to
look a little bit more in depth to
So the first thing is color, color is the
most
obvious but it's actually probably the
least helpful out of all physical
properties. I often compare, I compare
the color of minerals to the color of
people. You know it's just
it's the most obvious thing that you see
when you look at someone it's the first
thing you pick out the color of their
hair,
the color of their eyebrows, the color of
their skin, their teeth,  their eyes
But does that color that you're
observing
allow you to make  some form of association or some form of association or
some form of conclusion or oh because
their hair is this color that means they
must be like this type of person.
That doesn't mean anything it's an
obvious trait
but it's really probably the least
helpful. So when we learn to identify
minerals
that's even though it's the first thing
you see, we try to keep it to be the last
thing that we use, why? Well because like I said earlier
We can find that many minerals have
you know it may be one type of mineral
but different variations. So as an example we'll talk about this
is a quartz crystal,  this is a double
terminal quartz crystal. It has not been cut
this is the way it was collected but
this one in particular is considered
lemon quartz because it has a very very
light, you know yellow shade to it that's
within it. Well that being said there's yellow quartz,
there's smoky quartz, there's going to be
rose quartz which is more pink, there's
purple quartz which is amethyst. So again just because it's yellow
doesn't mean it's quartz, if it's yellow it can be quartz it could
be appetite it, could be a different
variation of fluorite i mean it doesn't
really narrow it down too much. So
although it is the first property we see
it's probably the least helpful
Moving forward the next one we have here,
so the little  bubble right here is luster
What does that surface look like as
it interacts with light? Well going back
to this piece of quartz, you can see that it's glassy right
Well what about this specimen here which
we'll talk about in a moment,
what does that look to you?  It looks
glittery it looks very metallic-y
Well that's a form of luster, maybe it looks very dull. Well when it's
very dull it can be earthy.
What about this specimen here I have?
You  know we can see it looks
it's not it's kind of shiny but I can't
see through it so maybe it's more like a
pearl
it's pearly, well that's what this would
represent
So luster is really just how does it
interact with light
So is it earthy more like a dirt tone, is
it metallicy
is it uh more of a gray piece you know
is it or is it maybe
silky or is it waxy. So it's just really
how does if you had to describe it to
someone who couldn't see it , what would
you say the surface looks like
The next one is hardness so how hard is
that mineral in relation to others
So it says here each mineral has a
measurable resistance to scratching
the Mohs scale orders the minerals in a
spectrum of one to ten
The, most boxes themselves come
in a box of one to nine. This is a mohs
hardness scale. Although this is you know this is the
most used the, mohs hardness scale.
But we have other ways that we can
identify the hardness other than using these variation of
minerals. So as we can see I'll kind of
zoom in a little bit we can start off
here with talc. Talc is in this corner here that's the
softest and then as we move towards
gypsum
calcite, we move into fluorite, apatite,
feldspar, quartz, topaz and corundum
They go from softest down to hardest, being corundum here in the box number 9 .
Number 10 is a diamond and I don't make enough to have one of those
So you have to believe me that it would
be there
So what we would do is we would use
these specimens within this box
to scratch unknown specimens so as an
example
maybe this is my unknown, so if I take my
number
one and my unknown and I scratch the
unknown with my number one
Well I can see that i left a mark that
this specimen is
harder than a one.  Well then i wipe it
off and I move to number two
and then I scratch it there and I keep
doing that until
the both specimens scratch each other
when they scratch each other that means
they are of equal hardness. So then i would go ah this unknown
specimen has a hardness of
six and I would write that down in my
notes and then I'd move on to my next
physical property and I'd work through
all of them to help me narrow down
what the unknown is.  I'm gonna hold
the box up one more time my mohs
hardness kit
to kind of put things in perspective
talc is very fine scratchable with a
fingernail,  it's much,  well they use it for talcum
powder moving down into corundum which
is number nine
that's just a poor quality garnet. A
garnet which is a gemstone so we can see
a nice little variation. We'll look more at this box in a moment
Streak is another one, minerals when they are scratched upon a
tile. This is a white
tile, they will sometimes leave behind
pigmentation. So which is really the powder form of
that specimen. That being said if you have something
that's harder than the tile, then it will
actually just scratch
the tile itself. Which means it does not
have a street color. Colors can range
from red to white, to blue to green. So what's
interesting about streak is that
sometimes, the streak might
actually be a different color than the
specimen that you're observing
And that will be another tool that will
allow us to identify
what it is and then the last one here is
cleavage and fracture
is due to the structure of its chemical
organization
Some minerals will either fracture or
break like glass would
or you know chip or it would cleave in a plane. Meaning that it has a nice clean cut
zone and we'll talk more about that but
that's certainly a helpful piece
in identifying. So as an example there's
a mineral called calcite and if I
smash calcite with a hammer it will
shatter but it will shatter
into the exact same shape that the
bigger one
the bigger sample was and that's a very
easy tool for us
So let's work through each one of these
very quickly, here's some examples of
color. So we can see here as an example these
are all different colors, here right.You've got some orange here
green, red, some grayish, brown, white
pink, brown, blue all these colors and
what's interesting about this example
I'm showing you here. These are all variations of quartz
of quartz it is. You're welcome I know
you laughed
You probably didn't that's okay. So these
are all different variations of quartz
meaning that there's just one thing
different in its final recipe
that allows it to be observed as a
different color
and because of that you may have a
different crystalline structure. What's
interesting there is that i've used the
word crystal
and I think that when most people use
the word crystal they think of
like a crystal like this milky quartz or
this one in my hand
again this lemon quartz. Well
yes this is a crystal but so are all
these other. Just because it doesn't look like this
doesn't mean it's not a crystalline
structure
So sometimes people are disappointed
when they see like this piece right here
in my hand which is
a form of,  it's orthoclase feldspar
Looking at this it's like well that's
not a very pretty crystal, it's like no
it's not but it really is still
a crystal. So we've got that, so that's
why i wanted to show different
variations of color
Obvious, it's the most obvious but
perhaps the least helpful. So again
oh just because it's green doesn't mean
it's quartz because look at how many
different variations of green there are. So that doesn't help us narrow down the
name from either adventuring or this practical light it doesn't
really help us there or jasper. Looking at luster again, luster is well
how does it appear you know to you when looking at light?
This is a metallic luster because it
shines like metal
maybe it's more glassy maybe it's more
you know
vitreous but fibrous maybe it's very
earthy like this piece here this is
called bauxite; b-a-u-x-i-t-e
Bauxite is a mineral that when melted
down
will create aluminum. This one here, look
at this perfect
square this is pyrite or fool's gold. So that's very metallicy in it's luster
So some examples of luster there. Again hardness here's a little hardness
kit. So you have talc which is talcum
powder
Gypsum which is used for drywall so it's
a little bit harder
Our fingernail is about the hardness of
a 2.5 a real one not those talons that
people glue on, liike a real fingernail is about a two
and a half. Calcite which is used as a cementing
agent is about a 3. Fluoride is four appetite would be 5
Feldspar would be 6. Since I've
mentioned Feldspar and Quartz
Quartz is 7. These are your most
common that we'll find
it's very rare that you'd walk around
and just pick one of these other ones up
on the ground. Most of what you pick up is a variation
of quartz or feldspar, in fact about 98 percent of the earth's
crust is a variation of quartz or feldspar
because these are the two most common
minerals
in granite and we know that our earth's
surface is predominantly
granite. So that being said 98 of that
crust is probably made out of quartz or
feldspar. Topaz which is a nice gemstone corundum
and then a diamond. This is a very fancy
hardness kit when I when I  was a student
and I took a basic geology course
you know we would have to buy one of
these boxes the mohs hardness kit this
way
So it comes with my oops, with my nine
specimens there
it also comes with a little magnet it
came with my little
streak plate and then every geologist
and earth scientist has one of these
You're 10 times magnifying your loop
lens and why is that important well
because sometimes specimens such as this in my hand here
have we can see that there's some
sparkle but maybe I want to see what
those crystals are a little bit bigger
and allows me to zoom in about 10 times
its size to be able to see that oh you know what
these minerals these, crystals are not like this type where
it's got a nice you know point to it. These might be a
little flakier  and that might allow me
to understand its design
Well why is that also important? Well
because yes
this is a quartz crystal, this is a very
large quartz crystal
maybe I''m looking at something that's
very very small and I can't see it
clearly. I need to look at it with my little loop lens
Streak, so here's some example of streaks
here we have your white tile four different minerals
and look they all leave different, I mean
they can
they're all gray in color but as you can
see each one leaves
a little bit different so as an example
here is my streak tile
and here is a metallicy mineral. To the observer it's silver in color so
here's my street plate and i'm going to try to do this
backwards so just hang tight. So here i am I'm going to scratch well
now that i've scratched if I kind of
zoom in a little bit you'll see that it
actually kind of has if I kind of smash it out a little bit
it's very red, it's a dark iron red well that's because this very
shiny mineral is called hematite and it's normally
observed in a reddish color when it
oxidizes
When it's in this shade now. you can see
my fingers this is you know
everyone's worst nightmare glitter. This
is a natural form of glitter and it gets
all over the place. Now that I've got it
on my hand it'll be on my face
for maybe two or three weeks. So
that's why it's helpful too because I'd
look at that metallic looking mineral
and go well I don't know what it is you
know. But then when I strike it upon a
streak plate I see that the
residue left behind is a dark red, I can
see that the mineral structure, the
the crystals themselves are you know
smaller and in blade you know
smaller pieces that allows me to
identify that oh this might be
a hematite and then there'd be some
additional tests I can look at. I can
see if my magnet sticks to it, if it does
or if it doesn't that will help me
identify it too. So different attributes these are pretty
easy. This one's the hardest which is cleavage or fracture
So meaning that does the mineral break into a special shape or does it just break like glass ?
So as an example, yes this crystal this quartz crystal is
really pretty, it's grown like this with two points but
if I smashed it, it would just break like
glass. Because this is you know, most of
our sand is made out of this here on the west coast.
We melt down sand to make glass, it makes sense. So you probably have broken a piece of glass before
and it just shatters right?  Yes,
that was that means. Well what about this
one here? This is that piece of feldspar
again
This is more blocky, when I think of the
word  blocky. I think of a broken
brick
Meaning that it's not a nice square, it's not a rectangle.
But it's broken enough that I could stack them. Because it has at least two good directions in which I
can observe. Meaning that it's got two, when we,  you can see the list here
When we talk about directions it means a set of sides
So let's kind of talk about that.The biotite and muscovite those are in
the mica family. They have one direction of cleavage
or two sides. Meaning that you can easily
see
that there's a flat top and a flat
bottom. We're using this little axe to
represent how it breaks. So it breaks
into sheets
So it just peels like paper. So it has a
nice top,  a nice bottom
Which means it has two sides or one
direction of cleavage
This is an example of orthoclase plate
or plagioclase feldspars
it exhibits two directions or two axes
coming and cutting it
at 90 degrees. So it's more blocky like a
broken brick
Okay so here we have this guy here
this is a piece of calcite which is
circled right here. As we can see it very clearly has one,
two, three, four, five, six. Six sides, right?
Which means that it has three really good directions of cleavage
as you know. When I  think of cleavage I
think of it as;  he used to have a top and a
bottom. Top, bottom there's one. Top bottom that's two.
Top bottom that's three. So  it has six sides  or three very nice planes.
If I drop this on my  desk, it would break into a bunch of little pieces
it would be the exact same thing. Another
fun fact about this though
is that, it has, I'll just use my field book. It has a
unique optical properties. This is a
field book of some notes
But if I show,  you see what it does?  It actually
doubles the image weird right?  So you can
see where the word rhino has been
doubled and that's part of its optical
properties. Galena is a perfect cube,  galena is in
the pyrite family, it's a lead ore and then
fluorite's really neat. Fluorite has four good directions or eight
sides. Fluoride, fluorite, fluorite
looks like a double pyramid
This has not been cut, this is the way it
is. But if I smashed it
it would break into that shape. It would
continue to get smaller and smaller
So what I have here are some, is a video
So when there are no perfect
surfaces, it will just break like glass.So this is a piece of glass right
this is a piece of silica, moving down
here
Breakage describes how it will break. So
look at this, they shatter this piece
here and look it breaks into
piece, it has a nice clean break this one
here.  I didn't make this video, this little
scene. From my observation it's
probably a piece of halite which is salt
which means it's going to break into
cubes
So that being said, rough course into
this . I totally get it, but what we're
able to do is, we're able to look at
specimens
and we're able to go through these
properties. So i'm going to go back to
that list, we're going to be able to go through
these properties to understand more, what this mineral might be
Again we know that there's thousands of
minerals. So usually what we would have
is a book and that book would allow us to break
this apart. But what we would do in the
field is I would sit down and go okay
I have an unknown specimen and I would
collect all this data
Well when I smash it with a hammer does
it break into smaller bits
or does it just shatter like glass. If I
strike it on a piece of tile
does it leave behind a residue of a
color?
How hard is it when using my my box set? 
What how does it look with light right?
You know does it, iss it more metallicy is it silky? Is it
does it look more earthy ? And then my last piece would
be okay what, what color do i observe what shade of
color? So these are some of your physical
properties and really the foundations of
how minerals are observed
That being said once we know this then
we're able to work towards rocks
Because rocks are made out of minerals. So maybe we don't know what the rock is
but using our handy dandy
10 times magnifying loop lens I'm able
to identify what minerals are in that
rock
Which will then allow me to identify the
rock itself
So again i know this was a lot but I
just wanted to give you some examples of
the properties that we look at
when understanding minerals and that
being said don't forget to check out the next video
The foundations of Rock Identification
and we'll talk soon
