Rocks & Minerals

1. Rocks & Minerals

2. Minerals Saddle-shaped pink dolomite crystals.

3. What is a Mineral? • Naturally Occurring • Inorganic • Solid • Definite Chemical Formula • Definite Crystal Structure Beryl Galena

4. Naturally Occurring • Formed by natural processes not in the laboratory. - Is an Ice Cube a mineral? - Is the ice on the wind- shield of a car a mineral? - What about the ice in your refrigerator?

5. Inorganic • Formed by inorganic processes; not living • Does not contain chains of carbon atoms

6. Solid • Not gas or liquid • H2O as ice in a glacier or a snowflake is a mineral, but liquid water in the ocean is not. • The element mercury is a metal that’s a liquid at room temperature/pressure. Liquid mercury is NOT a mineral!

7. Definite Crystal Structure • Highly ordered atomic arrangement of atoms in regular geometric patterns Pyrite K-spar Fluorite Kyanite 8 Tourmaline Fluorite

8. Crystal Structure of Ice

9. Definite Chemical Formula • Minerals are expressed by a specific chemical formula -Gold (Au) -Calcite (CaCO3) -Quartz (SiO2) -Pyrite (FeS2)

10. Composition of the Earth’s Crust • Eight Elements that make up over 98% of Earth’s Crust -Oxygen (O) -Silicon (SI) -Aluminum (Al) -Iron (Fe) -Calcium (Ca) -Sodium (Na) -Potassium (K) -Magnesium (Mg)

11. Where Do Minerals Come From? Crystallize from magma and lava. Olive crystallizes from mafic magma. Precipitate from water due to evaporation.

12. How Are Minerals Identified? • Color • Luster • Hardness • Streak • Density • Crystal Shape • Cleavage and Fracture • Special Properties

13. QUARTZ ROSE QUARTZ SMOKY QUARTZ Color • Usually the first and most easily observed -Some minerals are always the same color -Some minerals can have many colors

14. Luster • General appearance of a mineral surface in reflected light Glassy-Obsidian

17. Hardness • Resistance to scratching by different items; “scratchability” Mohs Hardness Scale >2 fingernail 3 penny ~5 Steel of a pocket knife 5.5 Window Glass 6.6 Steel of a file 7 quartz crystal

18. 9 10 Mohs Mineral Hardness Scale Softest 1) Talc 2) Gypsum 3) Calcite 4) Flourite 5) Apatite 6) Feldspar 7) Quartz 8) Topaz 9) Corundum 10) Diamond 1 5 2 6 3 7 Hardest 4 8

19. Streak • The color of a finely powdered mineral • Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate)

20. Density • The amount of matter in a given space (Mass/Volume)

21. Crystal Shape • Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming

22. Cleavage and Fracture • Cleavage is the tendency of a mineral to split or crack along parallel or flat planes Rhombohedral cleavage forms “smushed” cubes (calcite). Octahedral Cleavage forms bi-pyramids (Fluorite) One direction of cleavage = basal cleavage (biotite mica).

23. Cleavage and Fracture • Fracture occurs when a mineral breaks at random lines instead of at consistent cleavage planes. • Conchoidal fracture is what gives quartz, obsidian, chert, and flint those super-sharp edges! Quartz has no cleavage and instead exhibits conchoidal fracture.

24. Special Properties • Magnetism (Magnetite) • Optical Properties (calcite and ulexite) • Glowing under ultraviolet light (Fluorite) • Salty taste (Halite) • Smell (Sulfur) • Reaction to weak acids (Calcite) Magnetite

25. Economic Importance of Minerals • Minerals are in many things we see and use everyday such as; bricks, glass, cement, plaster, iron, gold

26. Every American Requires 40,000 Pounds of New Minerals per Year • at this level of consumption the average newborn infant will need a lifetime supply of: -795 lbs of lead (car batteries, electric components) -757 lbs of zinc (to make brass, rubber, paints) -1500lbs of copper (electrical motors, wirings -3593 lbs aluminum (soda cans, aircraft) -32,700 lbs of iron (kitchen utensils, automobiles, buildings) -28,213 lbs of salt (cooking, detergents) -1,238,101 lbs of stone, sand, gravel, cement (roads, homes, etc.)

27. Rocks

28. Rocks • Made of two or more different minerals that have been: • cemented together • squeezed and heated together • melted and cooled together.

29. Types of Rocks • Igneous • Sedimentary • Metamorphic

30. Igneous Rocks • Most igneous rocks are produced deep underground by the cooling and hardening of magma

31. Sedimentary Rocks • Formed from the breaking apart of other rocks (igneous, metamorphic, or sedimentary rocks) and the cementation, compaction and recrystallization of these broken pieces of rock

32. Fact about the Mississippi River Did You Know? • The Mississippi River carries an average of 436,000 tons of sediment each day • It moves an average of 159,000,000 tons of sediment a year

33. Metamorphic Rocks • Formed from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, igneous, or even another metamorphic rock.

34. The Rock Cycle • The diagram of the rock cycle shows how the earth's rocks are changed again and again

35. Classification of Igneous Rocks • Composition-refers to the minerals that make up the rock • Texture-shape, size, arrangement and distribution of minerals that make up the rock

36. Granite Composition • Extrusive- Formed from lava; volcanic • Intrusive- Formed deep within the earth Obsidian Pumice

37. Textures • Glassy • Fine-grained • Coarse-grained • Porphyritic Obsidian Granite Basalt Granite

38. Classification of Sedimentary Rocks • Clastic Rocks- Made of the fragments of previously existing rocks • Organic Rocks- Come from organisms • Chemical Rocks- Formed by inorganic processes such as evaporation

39. Clastics Rocks • Mudstone • Conglomerate • Sandstone

40. Organic Rocks • Limestone Coquina Fossiliferous Limestone

41. Chemical Rocks • Limestone

42. Metamorphic Rocks • Foliated-Parallel alignment of flattened mineral grains and pebbles • Unfoliated-Rocks that are not banded and do not break into layers

43. Foliated Gneisse

44. Unfoliated Marble

45. Distribution of Rocks in the U.S.