1. Minerals

2. What is a Mineral?
Naturally-formed solid substance with a crystal structure
Pyromorphite

3. What do all minerals have in common?
Are formed by natural processes.
Are NOT alive and NEVER were alive
Have a definite volume and shape
Are elements or compounds with a unique chemical makeup
Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)

4. Groups of Minerals
Minerals are grouped by the elements they are made of.
Beryl (Emerald)
Calcite
Amethyst

5. Contain oxygen & silica The most abundant group of minerals
Mineral Group
Characteristics
Examples
Silicates
Contain oxygen & silica
The most abundant group of minerals
Quartz, mica
MICA
Quartz

6. Mineral Group
Characteristics
Examples
Oxides
Metallic ion and oxygen
Hematite (Fe2)O3

7. Mineral Group
Characteristics
Examples
Sulfides
Sulfur and a metallic ion
Galena (PbS)

8. Metallic ion, Sulfur & oxygen Barite (BaSO4)
Mineral Group
Characteristics
Examples
Sulfates
Metallic ion, Sulfur & oxygen
Barite (BaSO4)
Barite BaSo4
Barite on Calcite BaSo4 / CaCO3

9. Halite (rock salt) (NaCl) Fluorite (CaF2)
Mineral Group
Characteristics
Examples
Halides
Include a halogen ion (group 17) and a metal from the left side of the periodic table
Halite (rock salt) (NaCl)
Fluorite (CaF2)
Halite
Fluorite

10. Carbon & oxygen and a positive ion, such as calcium Calcite (CaCO3)
Mineral Group
Characteristics
Examples
Carbonates
Carbon & oxygen and a positive ion, such as calcium
Calcite (CaCO3)
Calcite with Duftite inclusions

11. Mineral Group
Characteristics
Examples
Native Elements
Single elements
Gold (Au), Diamond (C), Silver (Ag)

12. How do minerals form?
1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle))
Fast Cooling = No Crystals (mineraloids)
Medium Cooling = small crystals
Slow Cooling = large crystals

13. How do minerals form?
2) Elements dissolved in liquids (usually water)

14. Physical Properties of Minerals (can be used to identify the mineral)
Color
Can be misleading
Can vary with the type of impurities

15. Physical Properties of Minerals (can be used to identify the mineral)
Luster
Surface reflection
metallic = shiny like metal
non-metallic = dull, non-shiny surface
Pyrite has a metallic luster
Quartz has a non-metallic luster

16. Physical Properties of Minerals (can be used to identify the mineral)
Streak
The color of the powdered form of the mineral
The color of the streak can be different than the mineral
Minerals must be softer than the streak plate

17. Streak…can help identify quartz
BUT...

18. Physical Properties of Minerals (can be used to identify the mineral)
Hardness
How easily a mineral scratches materials
Mohs Hardness Scale
Scale from 1 (softest) to 10 (hardest)
Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)

19. Find out more… “Electronic” Hardness Test

20. Physical Properties of Minerals (can be used to identify the mineral)
Cleavage & Fracture
The way the mineral breaks
Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape
Fracture—minerals that break at random with rough or jagged edges

22. Cleavage or Fracture? 1. 4. 3. 2.

23. Physical Properties of Minerals (can be used to identify the mineral)
Other Properties
Specific gravity (*excellent clue to mineral’s identity)
Attraction to magnets
Bending of light
Reaction with hydrochloric acid
Smell & taste