1. Ch 4. Minerals

2. What is a mineral? Naturally occurring Inorganic Solid
Specific chemical composition
Definite crystalline structure

3. Naturally Occurring Minerals are formed by natural processes
They are NOT man made

4. Inorganic They are not alive Salt is a mineral
Sugar is not because it was harvested from a plant.

5. Solid
Solids have a definite shape and volume

6. Specific chemical composition
Each mineral has a unique “recipe”
Quartz = SiO2
Calcite = CaCO3
Some minerals consist of a single element
Copper (Cu), Silver (Ag), Sulfur (S)

7. Definite Crystalline Structure
Atoms are arranged in a regular geometric pattern
Pattern is repeating
Minerals that form in an open space may grow into a single, large, well-defined crystal
This is rare
Most crystals form in a restricted space so their internal structure is not as obvious

8. Formation of minerals From Magma
Magma cools as it rises toward the surface of the Earth
Compounds in the magma begin to interact chemically
Magma cooling slowly results in LARGER crystal sizes
Magma cooling very quickly results in SMALLER crystal sizes

9. Formation of Minerals From solution
When a solution cannot dissolve anymore of a substance it is considered supersaturated
This may cause mineral crystals to precipitate out of the solution
The same can happen if the liquid evaporates

11. Mineral Groups Numbers Approximately 3000 known minerals
About 30 are considered common
10 make up 90% of the Earth’s crust
Oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium

12. Silicates
Consist of 1 silicon atom, 4 oxygen atoms and usually one or more other elements
Structure is called a tetrahedron. (pyramid)
Oxygen atoms can bond with one another in several different ways
Example – Olivine – Mg2SiO4

13. Carbonates
Consist of one or more metallic elements and a carbonate group CO3
Example – Calcite – CaCO3
Carbonates are the primary minerals found in limestone and marble

14. Oxides Compounds of oxygen and a metal
Examples – hematite and magnetite FeO3
Both are common and good sources of iron

15. Sulfides Compounds of sulfur and one other element
Example – FeS2 - Pyrite

16. Sulfates
Contains the sulfate compound SO4
Example – Anhydrite – CaSO4

17. Halides
Made up of Chloride and Fluoride along with Calcium, Sodium, or Potassium
Example – Halite – NaCl (salt)

18. Native elements Made up of a single element
Example – Silver and Copper