1. Notes: MINERALS!
( )

2. Characteristics that make a Mineral. . .
Naturally made
Solid
Inorganic (never living or from living things)
Unchanging chemical composition/formula
Crystal structure

3. General Facts about Minerals
Almost 4000 have been identified!
A few are “native elements” -- made of only one element that exists by itself, (such as gold or copper) and also rock-forming elements.
Most are compounds
Sometimes, compounds are only minerals when they’re in a certain phase of matter (ice, diamonds)
but not in others.
A gem is a valuable mineral that is prized for it’s appearance.

4. COMMON CHEMICAL GROUPS OF MINERALS:
“Silicates” (--SiO4) – Are pyramid-shaped groups, and can form chains and sheets very easily. Usually has a “glassy” sheen or specks when seen in rocks What type of bonding?

6. (3)“Oxides” and “Hydroxides” (--03 / --OH )
(2) “Carbonates” (--CO3) Can take on many appearances, but appear mostly powdery/chalky when broken down. These fizz with the acid test.
(3)“Oxides” and “Hydroxides” (--03 / --OH )
These contain metals combined with other elements. They can be very swirly and colorful looking.

7. Since there are 4000+ known minerals, there are tests in place to identify them:
Breakage: Cleavage vs. Fracture
Density (specific gravity)
Special properties --reaction to acid --fluorescence salty taste magnetism
Hardness
Crystal shape (form)
Luster
Color
Streak

8. Mineral Hardness Ability to scratch another mineral
To use the scale for example, a fingernail can only scratch what’s under it (Gypsum and Talc).
What ever is above you on the scale can scratch you. What ever is below, you can scratch.

9. Example: What minerals can scratch QUARTZ? What’s the hardest mineral?
What’s the softest?
What tools can scratch CALCITE?

10. Crystal Shape (Form) External shape
due to internal arrangement of the atoms (LATTICE) The longer the cooling time, the larger the crystals, because atoms have “time” to organize.
All minerals have crystals, even if it doesn’t look like it!

11. Crystal Formation. . . Minerals need to be dissolved in a solution
There needs to be a source of heat
They need to be left undisturbed for a long time
They need room for atoms to arrange in a lattice structure

12. Luster Describes how light reflects off the surface
Main categories are “metallic” and “non-metallic”
Non-metallic includes “dull,” “vitreous (glassy)”, “ waxy,” “pearly,” and others

13. Why????? . . . (What kind of bonding?)
Metallic elements can also be malleable (able to be pounded into different shapes)
Metallic elements can also be ductile (able to be pulled into wires)

14. Color & Streak
Overall color results from ability to absorb some wavelengths of light, and reflect others
Other color differences vary due to chemical differences or impurities (atoms mixed inside the main elements)

15. ….Streak
Color of the powder when rubbed on a “streak plate” (unglazed porcelain)
Some paint is based on powdered minerals (streaks).
Most minerals just have a white streak

16. Breakage: Cleavage vs. fracture
Some minerals split along flat surfaces when struck hard or pried apart--this is called mineral cleavage
Other minerals break unevenly along rough or curved surfaces--this is called fracture
A few minerals have both cleavage and fracture

17. Density (Specific Gravity)
All minerals have density (mass / volume), but some are very dense.
Examples include Galena, Magnetite, and Gold
Specific Gravity is the density of the mineral compared with density of water

18. Special Characteristics-- the “Acid Test”
Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO2 gas)

19. Special Characteristics-- Fluorescence
Some minerals will glow when placed under ultraviolet rays
Franklin and Ogdensburg, NJ are famous for their fluorescent minerals

20. Special Characteristics-- Salty Taste
DO NOT TASTE MOST MINERALS!
Halite is the exception--it will taste salty

21. Special Characteristics-- Magnetism
Many iron minerals will produce an invisible magnetic force field
“Lodestone” (Magnetite) was used by Vikings more than 1,000 years ago as compasses

22. ORE
A mineral-bearing rock who’s mineral is mined, purified, and sold for profit.
Examples: Bauxite is an ore of Aluminum