1. Introduction to Minerals

2. Objectives What are minerals?
What characteristics do all minerals share?
What roles have minerals played in our civilization?
Where do minerals come from and what are the processes by which minerals form?
What are the major groups of minerals?

3. What are minerals? atoms.
Minerals are a type of matter and we know that all matter is made of?
But more specifically, a minerals must meet five criteria to be called a mineral…
atoms.

4. SOLID Characteristic #1 All Minerals are…
Which of the following could be a mineral?

5. Characteristic #2 Inorganic= were never alive All minerals are
Which of the following could be a mineral?
Inorganic- was never alive
Organic- is currently alive

6. Characteristic #3
All minerals occur naturally.
If that is true, which of the following is not made of minerals?

7. Characteristic #4 All minerals have a definite chemical composition.
This means that in each individual mineral, certain types of atoms will come together (bond) in certain ways
Ex. this is similar to how 2 hydrogen's and one oxygen come together to form the most important molecule on Earth! O H H

8. Characteristic #5
The atoms in minerals are arranged into orderly structures called crystals.
Cubic
Tetragonal
Orthorhombic
Hexagonal

9. Why are minerals important to learn about?
A huge portion of Earth is made of minerals.
Most rocks are a combination of minerals.
Minerals provide nutrients to living things (like us) that allow us to live and thrive.
Many of the things we use every day are manufactured using minerals.
Can you think of any examples?

10. ***You should see lots of different minerals in every single rock
Minerals and Rocks
Coal
Gneiss
Scoria
Rocks are
combinations
of minerals
Minerals are
individual crystals
of all the same stuff
***You should see lots of different
minerals in every single rock

11. Examples: Amethyst Calcite Garnet Galena Gold Pyrite
***Notice how each is one single type of crystal!
Amethyst Calcite Garnet
Galena Gold Pyrite

12. Where do minerals come from?
Mineral crystals can form in two ways:
From stuff
dissolved in liquids
(Evaporation & Hot Water)
From Cooling
Magma & Lava

13. Minerals & Crystals from Magma & Lava
Extrusive Cooling:
Lava cools Fast
(Short Time = Small Crystals)
Minerals form from hot magma as it cools inside the crust, or as lava hardens on the surface.
When these liquids cool to a solid state, they form crystals.
Size of the crystal depends on time it takes to cool down.
Intrusive Cooling:
Magma cools slowly
(Long Time = Large Crystals)

14. individual crystals in Rhyolite
Minerals Crystal Size
When the hot material cools fast, it has smaller crystal size. When it cools slowly, it has large crystals.
Granite
You can see
individual crystals
in Granite
=cooled slowly
Rhyolite
You can’t see many
individual crystals in Rhyolite
=cooled very fast

15. Minerals formed by Evaporation
Some minerals form when solutions/mixtures evaporate:
When water evaporates, it leaves behind the stuff that’s dissolved in it.
Longer it takes to evaporate, the larger the crystal.
i.e. salt & water – ocean,
Halite, Gypsum, Calcite.
**All the white stuff = salt mineral crystals that formed
when the water of this lake evaporated.
The mineral material was left behind

16. These salt crystals formed from salt water because as the water evaporated, the salt wasn’t dissolved anymore. So the chemical energy in salt takes over and crystals form.

17. 3,000 minerals exist on Earth
Only around 20 are considered common
These minerals form rocks
10 of these make up 90% of Earth’s crust.
Quartz, orthoclase, Plagioclase, Muscovite, Biotite, Calcite, Dolomite, Halite, Gypsum, and Olivine/Pyroxene/Amphiboles.

18. Basic Properties Used to Identify:
Color
Cleavage
Hardness
Streak
Luster
Density
Crystal Shape

19. A black light really brings it out!
Special Properties
Some minerals display strange properties.
These can include: Magnetism, fluorescence, and reactivity.
Fizzing!
These minerals glow
in the dark.
A black light really brings it out!
The minerals in
this rock react
with acid
The particles of minerals
of this rock act like magnets

20. Rocks are made from Minerals
Rocks are nothing more than a mixture of different mineral crystals.
***All three minerals are
combined in a Granite rock
Granite
Quartz Biotite Feldspar =
(mineral)
(mineral)
(mineral)
(Rock)
This is Continental Crust

21. Rocks are made from Minerals
***Both minerals combined
make Basalt
Pyroxene Olivine = Basalt
This is Oceanic Crust
(mineral)
(mineral)
(rock)

22. Two Main Groups of Minerals
Silicate Minerals
96% of Earth’s crust
Composed of silicon (Si) and oxygen (O)
Quartz is pure Si and O, others contain other elements as well.
Non-Silicate Minerals
4% of Earth’s crust
Includes: Carbonates, Halides, Native elements, Oxides, Sulfates, and Sulfides.

23. Chemical composition Native elements Gold, Silver, Sulfur Au, Ag, S
Pyrite, Galena
FeS, PbS
Sulfides
Hematite, Magnetite
Fe2O3, Fe3O4
Oxides
SiO2
KAl2(AlSi3O10)(OH,F,Cl)2
KAlSi3O8
Quartz, Mica, Feldspar
Silicates

24. Silic- is for Silicon (s)
Silicates
Silic- is for Silicon (s)
-ate is a suffix for “oxide “
Silicates are “oxides of silicon”
Look at the reference table and calculate the weight of silicon and oxygen.

25. Silicates Mica Quartz Can you find the “silica” ? SiO2
KAl2(AlSi3O10)(OH,F,Cl)2
Can you find the “silica” ?

26. Silica Structure
4 oxygen atoms for every 1 silicon atom

27. Amphibole (Hornblende)
Complexity
Temp.
Olivine
Pyroxenes (Augite)
Amphibole (Hornblende)
Micas
Feldspar, Quartz

28. How can 2 minerals with the same composition be so different?
Graphite
Diamond
Chemical formula: C
Chemical formula: C
How can 2 minerals with the same composition be so different?

29. “Internal Arrangement of Atoms” controls most physical properties!
What’s the point here?
“Internal Arrangement of Atoms” controls most physical properties!

30. Review of Concepts: 1. Minerals can be identified by examining…..
Physical Properties, including….
Luster, Hardness, Cleavage, Color, Streak, Density….
2. Minerals are classified according to their…..
Chemical Composition, including groups like….
Native Elements, Sulfides, Oxides, and the all important SILICATES
3. The “Basic Building Block” of the Silicate Minerals is…..

31. Review of Concepts: (continued)
4. The physical properties of minerals are generally controlled by…..
Crystalline Structure….
…or the “orderly internal arrangement of the atoms”!
What do graphite and diamond have in common?……
Identical Chemical Composition….
What accounts for the differences between graphite and diamond?
….the “orderly internal arrangement of the atoms!