2. Mineral Characteristics I. Mineral Characteristics: I. Mineral Characteristics: A. Mineral - is a naturally occurring, inorganic solid with a definite structure and composition. B. There are more than 4000 minerals found on earth. C. All minerals share five characteristics. 1. All minerals are formed by one of three natural processes. A.) Formed from cooled magma. B.) Form from minerals dissolved in liquid. - After the water evaporates the mineral stays behind & dries. This forms the mineral. - Magma - hot melted rock under earth’s surface.

3. C.) New minerals could form from existing minerals. -They could be transformed by: -Heat -Pressure -Chemical Reaction -Mineral atoms change without melting, allowing the atoms to recombine in new ways.

4. Mineral Characteristics Cont. 2. All minerals are inorganic. A.) Minerals are not alive, never were, and were not made up by once living things. B.) Example: Is coal a mineral? Is Oil a mineral? Coal and Oil formed from one living things. 3. All minerals are solid and have a definite shape. A.) Liquids + Gases could never be minerals because they do not have a definite shape. 4. All minerals have definite compositions. A.) Some rocks are made of different things. 5. A mineral’s atoms are arranged in a definite pattern, that repeats over and over again.

5. Mineral Characteristics Cont. A.) The repeating pattern of atoms are called crystals. B.) When magma cools slowly, large crystals form. C.) When magma cools rapidly, small crystals form. II. Mineral Identification: II. Mineral Identification: A. Properties of minerals: 1. Appearance - you cannot rely on a minerals appearance alone to tell them apart. Ex. Gold and Pyrite (Fools Gold). 2. Hardness - is how easily a mineral can be scratched. A.) We can use hardness to identify minerals by using the Mohs Scale of Hardness.

6. “Mineral Identification Cont.” B.) An object with a hardness of 1 is the softest, and an object with a hardness of 10 is the hardest mineral. C.) Objects with the same hardness will scratch each other. D.) Which mineral is harder Quartz or Calcite? 3. Luster - Describes how light is reflected from the mineral’s surface. A.) Luster will be either metallic or nonmetallic. B.) Metallic - shines like metal. C.) Nonmetallic - does not shine like a metal. D.) Ex. Gold - metallic, Quartz - nonmetallic.

7. “Mineral Identification Cont.” 4. Color - Can help in identifying minerals. A.) Usually not enough. B.) Gold and Pyrite. 5. Streak - is the color of the mineral when it is broken up and powdered. A.) When a mineral is rubbed across an object with a greater hardness a streak of color is sometimes left behind. B.) Ex. Gold leaves a yellow streak, and Pyrite leaves a greenish brown streak.

8. “Mineral Identification Cont.” 6. Cleavage - Minerals have cleavage if it can break across a smooth flat surface. A.) Ex. A layer cake taken apart in layers is broken with perfect cleavage. B.) Halite and Calcite break with perfect cleavage. 7. Fracture - Minerals that break with rough or jagged edges have fracture. A.) Grabbing a chunk out of a layer cake would be like breaking a mineral with fracture. B.) Quartz has fracture.

9. “Mineral Identification Cont.” 8. Special Properties - some mineral have unique properties. A.) Calcite fizzes when Hydrochloric Acid (HCl) is put on it. Examples: B.) Magnetite is attracted to magnets. C.) Halite dissolves in water.

10. “The Rock Cycle” I. The Rock Cycle: A. What is a rock? 1. Rock- A mixture of one or more minerals, rocks, non-minerals, or organic materials. 2. Example- Granite is made of feldspar, quartz, mica, and hornblende. B. How are rocks formed? 1. Rock Cycle- The process by which over many years, this causes the changing of rocks from one kind to another.

11. 2. Three types of rocks are: a.) Igneous b.) Sedimentary c.) Metamorphic 3. These three types of rocks go through the cycle of one or more of the following: a.) Melting- Rocks are heated up and turned into magma or lava. b.) Lithification- The process of sediment being cemented or compacted into rock. (Sedimentary rock forms this way)

12. c.) Cooling- The process of magma or lava solidifying into solid rock. Igneous Rock Forms this way d.) Weathering & Erosion- The process of rocks breaking down into sediments and the movement of these sediments over time. e.) Effects of heat and pressure- when igneous, metamorphic or sedimentary rock are placed under heat and pressure a new rock forms. (Metamorphic Rock forms this way f.) See the rock cycle.

13. II. Types of Rocks: A. Igneous Rock Origin: 1. Forms when magma or lava cools into rock. 2. Magma- melted rock below the earth’s surface. 3. Why does the magma or lava cool? 4. First, magma is less dense than any surrounding rock layers, so it begins to rise to the surface.

14. 5. When magma reaches the earth’s surface it is called lava. 6. Lava then cools quickly and forms igneous rock 7. Magma can also cool slowly under earth’s surface and form igneous rock.

15. B. Classification of Igneous Rock: 1. Intrusive Rock- Type of igneous rock that forms when magma cools under earth’s surface. a.) Large mineral crystals. b.) Magma cools very slowly. This gives the magma time to form large mineral crystals. c.) Coarse grain texture.

16. 2. Extrusive Rock- Type of igneous rock that forms from lava that cooled above the earth’s surface. a.) Small mineral crystals. b.) Lava cools very quickly. This does not give the lava time to form large mineral crystals. c.) Fine grain texture.

17. “Metamorphic Rocks” I. Origin of Metamorphic Rock: A. Metamorphic Rock- The type of rock that forms from existing rock that is changed by heat, pressure, & chemical reactions. 1. Underground rocks are under heat & pressure. 2. Eventually, if under enough heat the rock will melt and form magma. 3. In areas where melting does not occur, the rock’s form will change.

18. 4. The pressure of the overlying rock squeezes the mineral grains together forming new or larger mineral grains. 5. This changes the rock’s identity. C. Examples: 1. Granite can be squeezed into Gneiss. 2. Shale can be squeezed into Slate. 3. Basalt can be squeezed into Schist. 4. Slate can be turned into Phyllite, then Schist, and eventually Gneiss.

19. II. Classification of Metamorphic Rocks: A. Metamorphic Rocks are classified into two groups. 1. Foliated Rocks- type of metamorphic rock created when mineral grains flatten and line up into parallel bands. 2. Non-Foliated Rocks- type of metamorphic rock created when mineral grains change, grow and rearrange, but do not form bands.

20. B. Characteristics of Metamorphic Rocks: 1. Foliated Rocks: a.) Bands of minerals are around the rock. b.) Can be easily separated along these bands. 2. Non- Foliated: a.) Bands of minerals are not present.

21. III. Origin of Sedimentary Rock: A. Sediments- Are loose materials such as rock fragments, minerals, and bits of organic material, that have been moved by wind, water, ice, and/or gravity. B. Sedimentary Rock- Rock formed when sediments are compacted or cemented together.

22. C. Where does the sediment come from? 1. The process of weathering & erosion. 2. Weathering- is the process that breaks rocks into smaller pieces. 3. Erosion- is the movement of the weathered material. IV. Sedimentary Rock Formation: A. Sedimentary rock can form two ways:

23. 1. Compaction- occurs when layers of small sediment become compressed by the weight of the layers above them. 2. Cementation- occurs when large sediments are “glued” together by minerals deposited between the sediments. B. Examples of Compaction & Cementation: 1. Compaction: a.) Mud compacted with your hands. b.) When it dries the mud forms a hard substance.

24. 2. Cementation: a.) Water dissolves natural cement makers. b.) Water then travels through the gaps in the sediment and deposits the cement material. c.) When dried, sediment sticks together. V. Classification of Sedimentary Rock: A. Are usually classified into three groups. 1. Clastic2. Chemical 3. Organic

25. B. Clastic Rock: 1. Clastic Rock- are made from the broken parts of other rocks. These parts can be compacted or cemented together. 2. Clastic rocks have two categories: a.) Conglomerate- rounded off sediment. b.) Breccia- sharp edged sediment.

26. C. Chemical Rock- form when minerals are precipitated from a solution or are left behind when a solution evaporates. This material is then compacted or cemented together. 2. examples: a.) Limestone- Calcium Carbonate is in solution in ocean water. When it comes out of solution limestone is deposited. b.) Rock Salt- Halite mixed with other minerals. When lakes and seas evaporate they often deposit rock salt.

27. D. Organic Rock: 1. Organic Rock- forms from the remains of once living things. 2. Examples: a.) Chalk / Coquina- form from the shells of living things that are compacted or cemented together. b.) Coal- Dead plant material compacted over millions of years.