Rocks & Minerals

1. Rocks & Minerals

2. Minerals

3. What is a Mineral? • Naturally Occurring • Solid • Inorganic • Definite Chemical Composition • Crystal Structure Never Sneeze in Denver, Colorado!

4. Naturally Occurring • Formed by natural processes not in the laboratory

5. Inorganic • Do not come from living things • Formed by inorganic processes • Does not contain chains of carbon atoms

6. Solid • Not gas or liquid -H2O as ice in a glacier is a mineral, but water is not

7. Crystal Structure • Ordered arrangement of atoms in patterns • Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming Apatite Feldspar Diamond Quartz 8

8. Definite Chemical Composition • Minerals are expressed by a specific chemical formula which tells you the types and amounts of elements found in a given type of mineral. • -Gold (Au) -Calcite (CaCO3) -Quartz (SiO2) -Pyrite (FeS2)

9. Characteristics of Minerals

10. Where Do Minerals Come From? Magma Evaporation

11. How do minerals form? • Crystallization from magma • Precipitation (rain, sleet, snow) • Pressure and temperature • Hydrothermal solutions (hydro=water, thermal = heat)

12. How Are Minerals Identified? Minerals are identified by a combination of properties that are unique to each type of mineral. • Color • Luster • Hardness • Streak • Density • Crystal Shape • Cleavage and Fracture • Special Properties

13. Hardness • The ability of a mineral to resist being scratched • Resistance to scratching by different items; “scratchability” • Mohs Hardness Scale Tool used to rank minerals from 1-10 1 is the softest 10 is the hardest • >2 fingernail • 3 penny • ~5 Steel of a pocket knife • 5.5 Window Glass • 6.6 Steel of a file • 7 quartz crystal

14. 9 10 Mohs Mineral Hardness Scale Softest 1) Talc 2) Gypsum 3) Calcite 4) Flourite 5) Apatite 6) Feldspar 7) Quartz 8) Topaz 9) Corundum 10) Diamond 1 5 2 6 3 7 Hardest 4 8

15. Tool used to measure

16. Streak • The color of the powder left when a mineral is scratched on a rough surface • Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate)

17. Luster • The way a mineral reflects light • General appearance of a mineral surface in reflected light Glassy-Obsidian

18. Economic Importance of Minerals • Minerals are in many things we see and use everyday such as; bricks, glass, cement, plaster, iron, gold • An ore is a rock that contains a metal or economically useful mineral.

19. Uses of Minerals • Minerals are also the source of metals, gems, food and medicines. A gemstone is a hard, colorful mineral that has a brilliant or glassy luster.

20. Every American Requires 40,000 Pounds of New Minerals per Year at this level of consumption the average newborn infant will need a lifetime supply of: • 795 lbs of lead (car batteries, electric components) • 757 lbs of zinc (to make brass, rubber, paints) • 1500lbs of copper (electrical motors, wirings • 3593 lbs aluminum (soda cans, aircraft) • 32,700 lbs of iron (kitchen utensils, automobiles, buildings) • 28,213 lbs of salt (cooking, detergents) • 1,238,101 lbs of stone, sand, gravel, cement (roads, homes, etc.)