Hello, my name is Kylie and welcome to minerals crystals and gemstones. Oh my my favorite thing, hmm
Do you know if a diamond is a mineral of crystal or a gem in this video
You'll learn to classify treasures of the earth into these special categories
Ready to get crystal clear. Let's go
Before watching this video
It's a good idea to watch the videos called the rock cycle and rocks
To learn how rocks are formed and classified then come back to this one
From the rock cycle video you learn that rocks are formed in different ways
Some form by a liquid solidifying some by layering and some by being pressured together
But do you know what really makes up a rock?
Rocks are mixtures of minerals and minerals form crystals
Every mineral has its very own special crystal
formation
But what is a mineral and what is a crystal?
Geologists scientists who study the earth agree that a substance must meet all five of these to be considered a mineral
It must be naturally-occurring
solid
inorganic a fixed chemical formula an
ordered crystalline structure
Let's look at what each item means?
Naturally-occurring means that is not made by a person a
Table is not naturally occurring because it is constructed by a person but the wood used to make the table is
Naturally occurring because it comes from nature
Does this wood make a mineral though?
Not so fast. Remember that a substance needs to meet all five criteria
Solid means that it is not a liquid or a gas
When it is at room temperature wood is a solid water is a liquid and air is a mixture of gases
Can would be a mineral now?
Not yet. We haven't looked at the next three items on the list
Inorganic means that the substance is not made by an organism or a living thing
Wood is made from a tree and a tree is an organism and living thing. Oh,
Oh, okay. So wood is definitely not a mineral
Now we get into a little chemistry
Having a fixed chemical formula means that the mineral has the same chemical makeup each time
for example
The mineral quartz is made up of silicon and oxygen atoms atoms are the basic tiny particles that make up all matter
When atoms join together, they can become molecules, but atoms cannot be divided into smaller parts
So every time that silicon and oxygen atoms combine in this form
Which is a fancy chemistry formula showing one atom of silicon and two atoms of oxygen. It is considered to be quartz and
Finally having an ordered crystalline structure means that the atoms that make up the mineral have a pattern
Don't worry, if the chemistry of minerals sounds confusing to you. You can still enjoy rocks and their minerals by how they look and feel
Let's study minerals in more detail because there are over 3000 types of minerals. It's really important to organize them into categories
So that we can keep track of all of them
There are eight common groups of minerals
native elements sulfides oxides phosphates sulfates carbonates halides and silicates
Whereas most minerals are made up of several chemical elements
Minerals considered to be mated elements are those in the purest form with only one element
Copper iron and graphite are considered to be native elements and are very commonly found
Gold platinum and silver are considered to be rare native elements
Which is why they are expensive to buy not all native elements are metals. However,
Sulfur and carbon are examples of nonmetallic native elements
Sulfides are made of sulfur plus another mineral usually a metal
Minerals in this group are known to be heavy brittle and metallic looking
Pyrite is a sulfide because it is made of sulfur and iron
It is often called fool's gold because it looks a lot like gold
Other sulfides are Galena cinnabar and stibnite
Oxides are minerals combining metal and oxygen
Hematite is often used in making jewelry and is also really great for meditation
Other oxides are magnetite cuprite and corundum
Phosphates are minerals made with phosphorus and oxygen
There are actually over 200 phosphates for the most common ones are turquoise and apatite
Phosphate minerals are often used for fertilizer, but also preservatives in food and cosmetics
Sulfates are made of sulfur plus oxygen and metal it
Is a soft mineral and often translucent which means it allows light through it. Even if we can't see through it clearly like glass
some examples of sulfates are gypsum barite selenite celestite and
anhydrite
Carbonates are a combination of carbon oxygen and metal
Examples are calcite rhodochrosite and malachite
This group of minerals is so soft that they dissolve with mild acids like vinegar
Halides are made by combining metal and one of these elements
Chlorine bromine fluorine iodine or astatine some of which dissolve in water
Highlight a rock salt is one example. Can you guess what highlight is used to make?
That's right table salt
fluorite and sylvite are other examples of halides and
finally silicates
Which is the largest group of minerals are made of oxygen and silicon quartz is the most common in this category. But so as amazonite
muscovite mica, and of course silicon other minerals in this category are
biotite labradorite talc and olivine
Rocks are made of minerals and minerals crystallise
When lava from a volcano cools the liquid particles come together and Harden creating a chemical bond
crystals begin to grow this means that the make up or atoms and molecules of these minerals are organized in a special way a
repeating pattern
Crystals don't only form from lava. However, they often form from a liquid when it starts to harden
Ice is an example of a crystal that forms when a liquid hardens
But another way crystals form is when a water evaporates from the mixture like salt water
when salt water evaporates it makes
salt crystals
Some other large crystals that you can see with the eye are diamonds and snowflakes
Snowflakes are crystals that form when water freezes
I bet you didn't know that many computer screens are made with liquid crystals
Each type of crystal has a different shape or color
Crystals can be cubic with a square structure like diamonds
hexagonal with a six-sided structure like emeralds
trigonal with a triangular structure like quartz
monoclinic which has a
parallelogram structure like azurite
Orthorhomic based on a rhombus or a diamond shape like celestite
tetragonal which has a rectangular structure like zircon and
triclinic which have random shapes like labradorite and
as you can see
Crystals can also be blue or purple or green or yellow or black or a combination of so many colors
Just like everything in science. There are some exceptions to the classification rules. For example
From the rocks video you'll learn that coal is a sedimentary rock and it's made with plant particles or organic
substances
It is also considered a mineral even if the rule of a mineral is made from inorganic substances
Geologists don't agree on the classification of coal. So you might see it classified as both a rock and a mineral
There are other tricky classifications that you may find as you study rocks and minerals more closely
For instance. How would you classify salt and sugar?
Salt is considered to be a mineral as we saw earlier, but sugar is not
How can that be when they are so similar?
Remember that in order to be a mineral the substance cannot be made from a living organism
Since sugar is made from plants sugar canes and sugar beets. It is not a mineral, even if it has crystals
When a crystal is so beautiful, it can be cut and polished it is called a gemstone or gem for short
Gems come in a variety of beautiful colors shapes and textures and they are often used to make jewelry
Diamonds emeralds rubies and sapphires are examples of popular gemstones used for jewelry
some other crystals that are often turn into gemstones are
amethyst amber, opal pearl topaz citrine tiger's eye
amazonite tanzanite agate and so delight
You have learned that rocks are made of minerals minerals. Crystallise
And when polished crystals can become gemstones Wow
Crystals and gemstones are so beautiful that many people like to collect them
Maybe you would like to start with your own collection
Or you can even try growing some of your own crystals such as bismuth crystals
But first apply all this knowledge by playing our fun online games and quizzes and remember to always be clever
okay, speaking of personal collections
I didn't bring all of mine today, but I thought I would share a few of my favorites. So first we have selenite
Now this quartz is a natural cut of quartz
Now you can get a thing called a tumbler at home or you can have different sheets of the crystal
so this one has been shaped and
Polished so a tumbler is a very fun thing to do at home
When you start out with a bunch of raw rocks, and then it goes through the tumbler and makes them smooth and shiny
Next we have fluorite. So this one is a lot like amethyst, but it's actually fluorite
Yeah, that's a fun one little cube cut'
But no matter what your collection does just remember to always be clever and have fun with it