1. Minerals The Building Blocks of Rocks

2. Natural Beauties The Hope Diamond

3. What is a Mineral? Naturally occurring Naturally occurring Inorganic Inorganic Solid Solid A definite chemical composition A definite chemical composition Orderly internal structure of atoms Orderly internal structure of atoms

4. Naturally Occurring Minerals are formed by natural processes Minerals are formed by natural processes Which one is a diamond and which one is a cubic zirconium? Diamond

5. Inorganic Minerals were never alive. Minerals were never alive. Salt crystals Sugar crystals Which one is a mineral? Both? Neither? – Salt is formed by evaporation – Sugar is harvested from a plant

6. Solid All minerals have a definite shape and volume All minerals have a definite shape and volume Solid goldLiquid gold Liquids and gases do not

7. Definite Chemical Composition A mineral can be represented by a specific chemical formula A mineral can be represented by a specific chemical formula Hornblende (Ca,Na,K) 2-3 (Mg,Fe 2+,Fe 3+,Al) 5 (SiAl)8O 22 (OH) 2 Quartz (SiO 2 )

8. Orderly Internal Structure Minerals are composed of atoms that occur in regular repeating patterns Minerals are composed of atoms that occur in regular repeating patterns Graphite (C)Diamond (C)

9. Where Do Minerals Come From? Magma Magma Solution Solution

10. Mineral Groups Nearly 4,000 minerals have been identified Nearly 4,000 minerals have been identified But only a few dozen minerals are called the rock-forming minerals But only a few dozen minerals are called the rock-forming minerals The most common elements found in Earth’s crust – Oxygen and Silicon The most common elements found in Earth’s crust – Oxygen and Silicon

11. Mineral Groups Silicates Most common mineral group Most common mineral group Contain silicon-oxygen tetrahedron Contain silicon-oxygen tetrahedron Four oxygen atoms surrounding one Silicon atom Combines with other atoms to form the various silicate structures Combines with other atoms to form the various silicate structures

12. Common Silicate Minerals

13. Mineral Groups Non-silicates Major Groups Major Groups –Oxides –Halides –Sulfides –Sulfates –Carbonates –Native elements

14. How to Identify Minerals Crystal form Crystal form Luster Luster Color Color Streak Streak Hardness Hardness Cleavage or Fracture Cleavage or Fracture

15. Property of Minerals Crystal Form External expression of the internal arrangement of atoms External expression of the internal arrangement of atoms Halite atomic structure Halite crystal Good crystal formFormed in a confined space

16. Property of Minerals Luster The appearance of a crystal when reflected in light The appearance of a crystal when reflected in light – Metallic Two categories – Nonmetallic – pearly, vitreous (glassy), dull, earthy pyrite graphite

17. Property of Minerals Color The most noticeable property to identify The most noticeable property to identify The most unreliable characteristic Varieties of Quartz

18. Property of Minerals Streak Color of a mineral in its powdered form Color of a mineral in its powdered form Magnetite Hematite

19. Property of Minerals Hardness A measure of how hard or easily a mineral can be scratch A measure of how hard or easily a mineral can be scratch Mohs Hardness Scale MineralHardness Talc1(softest) Gypsum2 Fingernail (2.5) Calcite3 Penny (3.5) Flourite4 Iron Nail (4.5) Apatite5 Glass (5.5) Feldspar6 Steel file (6.5) Quartz7 Streak plate (7) Topaz8 Scratches Qz Corundum9 Scratches Topaz Diamond10(hardest) The most reliable test for mineral identification The most reliable test for mineral identification Used minerals easily found in nature Used minerals easily found in nature

20. Property of Minerals Cleavage Tendency to break along planes of weak bonds Tendency to break along planes of weak bonds Three examples of perfect cleavage Flourite, Halite, Calcite Produces flat, shiny surfaces Produces flat, shiny surfaces

21. Property of Minerals Cleavage CleavageType # of faces DescriptionExamples Fracture0 No cleavage Quartz Basal1 Flat fragments, flakes Biotite Prismatic2 May or may not be at 90 degrees Feldspar Cubic3 At 90 degrees Halite Rhombic3 NOT at 90 degrees Calcite Octahedral4 Triangular cleavage faces Fluorite

22. Property of Minerals Fracture Some minerals break along uneven surfaces Some minerals break along uneven surfaces Quartz exhibiting “conchoidal” fracturing

23. Property of Minerals Other Properties Taste Taste Smell Smell Feel Feel Magnetism Magnetism Malleable Malleable Reaction to HCl Reaction to HCl Sulfur Calcite Chlorite

24. Mineral Resources Gems are valuable minerals that are prized for their rarity and beauty Gems are valuable minerals that are prized for their rarity and beauty Ores are useful metallic minerals that are mined for a profit