1. Minerals

2. The scientist does not study nature because it is useful
The scientist does not study nature because it is useful... He studies it because he delights in it, and he delights in it because it is beautiful.
- Henri Poincare

3. To be considered a mineral, the substance must be...
1. Solid
2. Inorganic = not alive
3. Formed by natural
processes
4. Element or compound
with a definite composition
5. Crystalline (have atoms
arranged in regular patterns)

4. Regular arrangement of atoms (lattice) in silica (Si)
Tunneling electron microscope (TEM) image of atoms. TEM sees more than one layer of the lattice. This image is about 3 nanometers (nm) across.

5. Baking soda NaHCO3
Table salt (halite) NaCl

6. 6 Main Crystal systems

7. From magma when it cools (volcanoes, igneous processes)
When a liquid, with minerals dissolved in it evaporates (lakes and oceans)
Formation of minerals
Magma:
melted rock deep inside the earth; called lava when found on the Earth’s surface

8. Properties of minerals
Color
Streak
Luster
Cleavage/fracture
Hardness
& other properties...

9. 1. Color
Color is not a very reliable way to recognize minerals. Many minerals may be totally different in chemical composition but have the same color. For example: emeralds and dioptase are different minerals but both are green. At the same time, the same mineral often can have many colors, for example: quartz has many colorful varieties.

10. 2. Streak
Streak is the color a mineral leaves behind when it is scratched on a porcelain plate, or when is powdered.
Note: only minerals softer than the porcelain plate will leave a streak.
Example: graphite - used in pencils- leaves a streak on paper.

11. 3. Luster
Luster describes how light is reflected from a mineral’s surface
Luster may be described as metallic or nonmetallic.
metallic - shines like a metal.
Examples: gold, galena, pyrite
nonmetallic - does not shine like a metal, it is glassy, pearly, silky, etc.
Examples: halite, hornblende

12. 4. Cleavage or Fracture
This property describes the way a mineral breaks. It depends on the arrangement of the atoms in the mineral.
Minerals that exhibit cleavage break along smooth, flat surfaces. Example: mica which always separates into flat slices, or halite that breaks into cubic shapes.
Minerals with fracture break forming rough, jagged edges. Example: quartz, chalcopyrite

13. 5. Hardness
This property is a measure of how easily a mineral can be scratched.
We use the Mohs Scale of Mineral Hardness.
Minerals are given a hardness number between 1 and 10:
1 = softest, ex. talc
10 = hardest, ex. diamond

14. Talc

15. 6. Other Properties
These properties, once observed, allow to recognize minerals very quickly:
magnetic properties (ability to attract magnets),  Ex. Magnetite.
reaction with HCl acid (fizzing)  Ex. Calcite.
double refraction (ability to strongly refract or bend light) - as a result you see a double image  Ex. Calcite, Ulixite
Taste, for example Halite = salt = salty taste.

16. 6. Other Properties Taste, for example Halite = salt = salty taste.
Only taste minerals Mrs. Moore says to taste. There is a correct way to safely taste a mineral.

17. Specific Gravity
In addition, to recognize minerals we measure their specific gravity.
Specific gravity is the ratio of the mass of the mineral to the mass of water displaced by the mineral when submerged. Specific gravity shows how many times as dense as water the mineral is.
Unlike density, specific gravity does not have a unit.

18. Mineral Classification
Silicates: contain Silicon and Oxygen, also other elements), Ex. Mg2SiO4, or SiO2
Oxides: metals bonded with Oxygen, Ex. Al2O3
Hydroxides: metals
bonded with OH
Ex. Al(OH)3
Mineral Classification

19. Mineral Classification
Halides: contain metals bonded with Chorine, Fluorine, Bromine or Iodine, Ex. KCl, or CaF2
Mineral Classification
Sulfides: contain metals bonded with Sulfur, Ex. PbS, or FeS2

20. Mineral Classification
Sulfates: contain metals bonded with SO4,
Ex. CaSO4·2H2O
Carbonates: contain metals bonded with CO3,
Ex. MgCO3
Mineral Classification

21. Mineral Song!