1. Rocks and Minerals Chapters 10-11

2. Rocks  Earth’s crust is made of rock.  Rocks are mixtures of minerals and sometimes other materials.

3.  When studying a rock sample, geologists observe the rock’s:  Color  Texture  Chemical composition

4.  Most rocks are made up of grains, particles of minerals, or other rocks.  Texture is the look that results from:  Size  Shape  Pattern of rock’s grains

5.  Coarse-grained-- large/easy to see.  Fine-grained – small, even microscopic.

6.  Grains in rock often form a pattern.

7.  Flat layers (strata)

8.  Wavy, swirling patterns

9.  Rows of beads

10.  Random or no pattern

11.  Some rocks have NO grain, because they cooled too quickly when they formed.

12. There are 3 groups of rocks:  Igneous  Metamorphic  Sedimentary

13. Igneous Rocks Formed from the cooling of molten (melted) rock. Examples: pumice, granite, basalt

14. Sedimentary Rocks Formed when particles of other rocks, plants, or animals are cemented together. Examples: Sandstone, breccia, siltstone

15. Formed when existing rock is changed by heat, pressure, or chemical reactions. Examples: gneiss, schist, phyllite Metamorphic Rocks

16. The Rock Cycle

17. Minerals  A mineral:  occurs naturally  Is inorganic  Is solid  Has a crystal structure  Has a definite chemical composition

18. Minerals  There are 3000 minerals.  100 are common.  20 minerals make up most of the rock’s of Earth’s crust (rock-forming minerals).

19. Mineral Formation  Minerals form through:  Crystallization of melted materials.  Crystallization of materials dissolved in water.

20. Crystals  Repeating patterns of a mineral’s particles that form a solid.

21. Minerals  All minerals contain certain elements in definite amounts.  Most minerals are compounds (two or more elements).  Silver and gold are considered minerals.

22. Mohs Hardness Scale The Mohs hardness scale ranks ten minerals from softest to hardest. 1 3 5 9 Diamond Talc 1 Gypsum 2 Calcite 3 Fluorite 4 Apatite 5 Feldspar 6 Quartz 7 Topaz 8 Sapphire 9 Diamond 10

23. Minerals are ranked according to:  Color

24.  Streak– the color of a mineral’s powder.

25.  Luster – how shiny a mineral is.

26.  Density—mass per unit volume (specific gravity)

27.  Cleavage – breaking of a mineral along a regular line.

28.  Fracture – irregular breaking of a mineral.

29. Fluorescence Minerals that glow under ultraviolet light.

30. Magnetism Magnetism occurs naturally in some minerals, such as magnetite.