Understanding Minerals

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?