1. Minerals are not made by people; they are … …naturally occurring substances.

2. Minerals Natural Solid Inorganic Definite chemical composition Crystal structure due to internal arrangement of atoms http://www.minerals.net/gemstone/index.htm

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

4. 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 Calcite has a non-metallic luster

5. Physical Properties of Minerals 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)

6. Tendenza a rompersi lungo piani paralleli alle facce dell’abito cristallino. Determinata dal reticolo Sfaldatura (Cleavage)

8. 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

9. 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

10. Streak…can help identify quartz http://www.childrensmuseum.org/geomysteries/cube/b3.html

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

12. Mineral GroupCharacteristicsExamples Non-Silicates Make up only 5% of the Earth’s crust Include some of the most important minerals iron, copper, gold, silver, diamonds, rubies Silver Gold Ruby Iron Copper Diamond

13. Mineral GroupCharacteristicsExamples CarbonatesCarbon & oxygen and a positive ion, such as calcium Calcite (CaCO 3 ) Calcite with Duftite inclusions

14. Mineral GroupCharacteristicsExamples Oxides  Metallic ion and oxygen Hematite (Fe 2 )O 3

15. Mineral GroupCharacteristicsExamples Sulfides  Sulfur and a metallic ion Galena (PbS)

16. Mineral GroupCharacteristicsExamples Sulfates  Metallic ion, Sulfur & oxygen Barite (BaSO 4 ) Barite on Calcite BaSo4 / CaCO3 Barite BaSo4

17. Mineral GroupCharacteristicsExamples Native Elements  Single elements Gold (Au), Diamond (C), Silver (Ag)

18. Mineral GroupCharacteristicsExamples Silicates Contain oxygen & silica The most abundant group of minerals Quartz, mica MICA Quartz

19. Special Characteristics the “Acid Test” Carbonates react with dilute HCl and other acids by fizzing or bubbling (releasing CO 2 gas)

20. Special Characteristics Fluorescence Some minerals will glow when placed under short-wave or long-wave ultraviolet rays http://www.sterlinghill.org/Tour%20information.htm

21. Special Characteristics Salty Taste DO NOT TASTE MOST MINERALS! http://mineral.galleries.com/scripts/item.exe?LIST+Minerals+Halides+Halite

22. Special Characteristics Magnetism Many iron minerals will produce an invisible magnetic force field http://www.minerals.net/mineral/oxides/magnetit/magneti4.htm

23. What do all minerals have in common? All: 1.Are formed by natural processes. 2.Are NOT alive and NEVER were alive 3.Have a definite volume and shape 4.Are elements or compounds with a unique chemical makeup 5.Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)

24. 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

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

26. 1.What element are diamonds made from? 2. What do all crystals have in common?

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

28. 1. If a mineral can scratch your fingernail, the mineral is _______________ than your fingernail. 2. What is luster?

29. Review