1. Minerals Chapter 3

2. Chapter 3.1 Mineral Structure A mineral is a naturally formed, inorganic solid that has a definite crystalline structure. You can tell whether an object is a mineral by asking four questions.

3. Chapter 3.1 Is it a nonliving material? Is it a solid? Does it have a crystalline structure? Is it formed in nature?

4. Chapter 3.1 Mineral Structure… To understand what a crystalline structure is, you need to know a little about the elements Elements are pure substances that cannot be separated or broken down into simpler substances by chemical means.

5. Chapter 3.1 Mineral Structure… Minerals may be either elements or compounds. A compound is a substance made of atoms of two or more different elements joined by chemical bonds.

6. Chapter 3.1 Mineral Structure… A mineral that is composed of only 1 element is called a native element. Ex.) Gold and silver are examples of native elements.

7. Minerals composition and Groups 90 elements occur naturally in the Earth’s Crust 2 groups of minerals: 1.) Silicates This means they are made of Oxygen and Silicon Make up 90% of Earth’s crust 2.) Non-Silicate Minerals Anything not made up of Oxygen and Silicon Ex.) Copper, Flourite

8. Mineral Identification: Mineral characteristics can help you identify them When we identify minerals we look at 6 areas: -1.) Hardness -2.) Luster -3.) Density -4.) Streak -5.) Cleavage and Fracture -6.) Color

9. 1.) Color Same mineral can come in many colors Why? Impurities in the mineral can create different colors

10. 2.) Luster: Is the way that a mineral reflects light -They can be a metallic luster (shiny like a piece of metal) They can also be non-metallic -Ex.) Quartz -Can be dull, pearly, silky, and glassy

11. 3.) Streak: Is the color of a mineral in its powdered form Gold is yellow and Pyrite is greenish-black

12. 4.) Cleavage and Fracture: Minerals that break along smooth flat surfaces have cleavage Fracture: is when minerals break with uneven, rough, jagged edges

13. 5.) Hardness: Is the measure of how easily a mineral can be scratched 1824- Friedrich Mohs came up with a list of common minerals to compare hardness with

14. 6.) Density: Is the comparison of the minerals weight to that of an equal volume of water Ex.) Gold and Fool’s Gold (Pyrite) -Gold is about 17 while Pyrite is only 5

15. Other properties: Sometimes we identify materials by their other properties ex.) Magnetism: Lodestone ex.) Reaction with acid: Calcite

16. 3.3: Mining and Minerals 2 types of Mining: 1.Surface Mining (strip mining) Open Pit-Coal Quarries-Iron 2.Subsurface Mining Tunnel Mining (Gold and Silver) All mining must be responsible!!! Reclamation: all land used for mining is returned to nature (1970’s)

17. Useful Elements in Minerals Ore: if a mineral or rock contains a useful substance that can be mined for profit Metallic Ex.) Aluminum Non-metallic Ex.) Calcite -concrete

18. Gems Ever walked past a jewelry store? What makes minerals so unique?

19. Properties of Gems Gems are highly prized minerals because they are rare and beautiful They can be clearer They can be brighter They can also be more colorful *Table 2 on pg. 74 and 75

20. Important Gems… All gems are prized but some are amazing -These gems played an important part in history Cullinan Diamond of South Africa -Largest diamond ever discovered -3,106.75 carats Blue Hope Diamond -530.20 carats, belongs to Britain

21. Useful Gems… Some gems have useful properties Diamonds are used on drill bits and blades Quartz is used with electronics and time pieces Rubies can be used to make a specific type of laser