1. Chapter 5 Minerals of Earth’s Crust

2. Define Mineral. Give one example.

3. Section 1 What Is a Mineral? Minerals are: Naturally occurring, Usually inorganic solid, Characteristic chemical composition, Orderly internal structure, Characteristic set of physical properties.

4. Four basic questions: 1. Is the substance inorganic? 2. Does the substance occur naturally? 3. Is the substance a solid in crystalline form? 4. Does the substance have a consistent chemical composition? See Table 1 page 103 Section 1 Characteristics of Minerals

5. More than 3000 known mineralsMore than 3000 known minerals Fewer than 20 common mineralsFewer than 20 common minerals Section 1 Kinds of Minerals

6. 10 common minerals make up 90% of the mass of the Earth’s crust. All minerals can be classified into 2 types. –Silicates –Nonsilicates Section 1 Kinds of Minerals

7. Rocks are aggregates (mixtures of minerals)

8. Chapter 5 Silicate Minerals A mineral that contains a combination of silicon and oxygen, and that may also contain one or more metals Common silicate minerals include quartz, feldspars, micas,and ferromagnesian minerals, such as amphiboles, pyroxenes, and olivines. Section 1 Kinds of Minerals

9. Nonsilicate Minerals A mineral that does not contain compounds of silicon and oxygen Nonsilicate minerals comprise about 4% of Earth’s crust. Examples: Dolomite, Halite, Silver, Corundum, Calcite, Gypsum, Pyrite, and Galena. See Table 2 Page 105 Skip Pages 106-108 Section 1 Kinds of Minerals

10. Mineralogists A person who examines, analyzes, and classifies minerals. Section 2 Identifying Minerals

11. Physical Properties of Minerals Many properties can be identified by just looking at a sample of the mineral. Other properties must be identified through simple tests. Section 2 Identifying Minerals

12. Five special properties that may help identify certain minerals Color Streak Luster Cleavage and Fracture Hardness Section 2 Physical Properties of Minerals

13. Color unreliableWhile color is a property that is easily observed, it is unreliable for the identification of minerals. The color of a mineral sample can be affected by the inclusion of impurities or by weathering processes.

14. Color- These are all quartz with different minerals in them.

15. Streak- the color of a mineral in powdered form Streak is determined by rubbing some of the mineral against an unglazed ceramic tile called a streak plate. Much more reliable than color. The streak may differ from the solid color of the mineral. Minerals harder than the ceramic tile will leave no streak.

16. Streaks

17. Luster A mineral is said to have a metallic luster if the mineral reflects light as a polished metal does. All other minerals have nonmetallic luster. There are several types of nonmetallic luster, including glassy, waxy, pearly, brilliant, and earthy.

18. Luster- the way in which a mineral reflects light

19. Cleavage and Fracture Cleavage- the tendency of a mineral to split along specific planes of weakness to form smooth, flat surfaces Fracture- the manner in which a mineral breaks along either curved or irregular surfaces

20. Cleavage-

21. Fracture-

22. Hardness Hardness is a measure of a minerals ability to resist scratching. Hardness does not mean it will not break. Mohs hardness scale the standard scale against which the hardness of minerals is rated.

24. Crystal Shape

25. Chapter 5 Density Is the ratio of the mass of the mineral to the volume of the mineral. Some minerals feel heavier than others.