Hi, everyone in this video. We're going to be talking about Minerals, so let's get started
What are minerals anyway well in the simplest sense of the term minerals are the building blocks of rocks?
Here's a rock. This is a piece of the igneous rock called granite if you look carefully at this chunk of granite
You'll see all sorts of speckles of Gray and white and black and if you [zoom] in
You'll see that these are [actually] crystals mineral crystals this particular piece [of] granite has the mineral quartz
Biotite Mica and Plagioclase feldspar
We'll study these more detail later on
so on Earth [there] are over 2,000 varieties of minerals some of which are seen here as
You can tell they come in a wide variety of colors shapes sizes
textures and all Sorts of different physical characteristics
Minerals have quite a few uses in our everyday life just to give you an example this here is an rough uncut diamond of
Course we use diamonds for jewelry we also use diamonds in construction [applications] as the tips of saw blades
And variety other industrial uses
Here's another mineral. This is called fluorite
most famous for its inclusion in
Toothpaste yes, when you see the name fluoride on a toothpaste that means it's made out of the mineral fluorite
But what else are minerals used for well this here is talc?
Talc is a very common mineral that is ground into a fine powder. It's very soft, and it's used in baby powder
Sometimes you might hear it referred to as talcum powder
One more example. This is a mineral selenite gypsum
Which is used all around us in drywall. This is the material that's used to build the walls inside Modern houses and buildings
But what exactly makes a mineral a mineral
Well to be considered a mineral the substance must meet five criteria
Let's go through those five [criteria] right now
number one
Substance must exist as a solid under normal conditions on Earth this means if you have [a] liquid or gas
Under normal conditions it cannot be considered a mineral it must be in the solid state
number two the substance must be
Naturally occurring on Earth this means it cannot be man-made
So for example plastic is not considered a mineral because it doesn't exist naturally. It's created by humans
Must be naturally-occurring
number three the substance must be in
organic meaning not coming from living or made of living things
so if you talk about
I don't know tree branches or leaves
They cannot be considered minerals because they are organic that is they came from living organisms
another example would be coral Coral is made by [small] sea creatures and
Therefore its organic material and cannot be considered a mineral minerals must be in organic
number four the substance must have a
Fixed chemical formula meaning it's made up of a specific combination of elements
Let me give you an example the mineral quartz is composed of silicon and Oxygen bonded together
Specifically one silicon bonded to two oxygen atoms all quartz is made of this chemical formula
another example pyrite
Often known as fool's gold has a chemical formula of fe which is iron and s which [is] sulfur
and when these are bonded together in this particular arrangement you get pyrite
so criteria for is that the substance must have a
Specific or fixed chemical formula has to be made of a specific recipe if you will of elements
And then finally criteria number five the atoms that make up the substance must be arranged in an orderly
Crystal structure a specific structure let me give you an example of this
[the] majority [of] the Minerals that [exist] on Earth's surface are considered silicates
And that means they're made up of in part silicon and oxygen
the Silica Tetrahedra is the most common arrangement of
Silicon and oxygen atoms within a mineral it looks something like this model here where the red balls of clay?
Represent Oxygen atoms and the Gray is a silicon atom and you can see they're bound together in this
Tetrahedral shape and this becomes the most common building block of Minerals on Earth
So that's what we mean when we say the atoms must be made up of a specific orderly structure
I'll give you another [example] of that in [just] a minute
So let's test ourselves a little bit here are those five criteria must be solid
Naturally occurring Inorganic have a fixed chemical formula and a specific atomic arrangement
So what about this pool of liquid Mercury can this be considered a mineral?
Well if you look at Criterion number one it says it must be a solid and this clearly is a liquid so
Sorry mercury. You're not a mineral
What about this chunk of bituminous coal?
Well, if you know anything about coal, you would know that it's actually formed from ancient
Tropical plants that have been compressed and squeezed together for millions of years
so it is [a] solid and it's certainly naturally occurring but
Because it's made from plants it is organic and therefore. It doesn't meet criteria number three and so coal is not
Considered a mineral
Well, what about ice this is an interesting one. Let's go through our Criteria. Is ice solid yes?
And it does exist as a solid [on] at least some parts of the Earth the poles
Specifically and high up at mountains you get water that exists naturally as a solid so that's fine
Is it naturally occurring of course?
There's quite a bit of ice naturally existing on Earth it is not an organic material
It is not living it never was living and it's not made by living things
It does have a fixed chemical formula H2o and it does have a specific atomic arrangement
So is it a mineral well according to our criteria? Yes, it is
However, there's a lot of debate about this and some people think ice should not be considered it because most places on Earth it would
Exist [as] [a] liquid [so] we'll give that one a question mark
What about this substance this is sulfur as you can see sulfur exists as a solid. That's good
It's naturally occurring it forms along volcanoes [it] is Inorganic
It's not living and it never was living it has a specific chemical formula
It's composed of the element sulfur, and it has a very specific
Atomic arrangement if we could zoom in we would see the atoms arranged in a specific way
So for our criteria to be met sulfur works, so it is considered a mineral
now let's move on I
Want you to keep in mind that all [of] the physical properties of a mineral and what I mean by that is the colors
the shapes the textures the smells and the tastes the
appearance the Hardness the [sheen] all of these physical
characteristics of minerals
Result from one specific [thing] and that is the internal
arrangement of the atoms
To give you an example that sulfur
We were just looking at is yellow the reason it appears yellow is because of how these sulfur atoms are arranged inside
Quartz sometimes appear clear, and that's because of how the atoms are arranged the mineral halite
Tastes salty because of how the atoms are arranged
The Mineral sulfur again has kind of a rotten egg smell and that's a result of the internal arrangement of atoms
So all of the physical properties result from how those atoms are arranged. Let me give you one really neat example of this
This is a diamond the hardest mineral that exists on Earth
Fairly Rare in
Nice complete crystals it is the hardest substance
It has a hardness of ten on something called the mohs hardness scale which we will learn about
now
Diamond is composed of one element and that is carbon if you could zoom down inside this diamond
You would see the cardem Carbon atoms arranged in a pattern like this
Notice how all the atoms are interlocking connected to one another [this] creates a really strong bond
Which is what makes time in such a hard mineral?
But let's look at a different mineral
Did you ever wonder what made a pencil right a lot of people have the misconception that [it's] lead?
It's actually not lead it's a mineral known as graphite
Interestingly enough graphite like diamond is made up of only carbon
But if you look at how the carbon atoms are arranged, they're arranged into these sheets which are not very well connected
The result is that though it's made of the same elements as diamond. It's a much much softer
weaker Mineral
So again what gives these minerals their physical characteristics is how the atoms are arranged inside?
So let's do a quick recap
First thing we talked about was [how] minerals are the building blocks of rocks how they have lots and lots of uses on Earth
To be considered a mineral it must meet our five criteria
It must be a solid it must be naturally-occurring it must be Inorganic
It must have a specific composition and finally it must have a definite structure
Thanks for listening