Minerals. What are minerals and how do we classify them?

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1 Minerals What are minerals and how do we classify them? 1

2 Minerals! Minerals are the ingredients needed to form the different types of rocks! Rock - is any naturally formed solid that is part of Earth or any other celestial object 2

3 Minerals! Mineral - naturally occurring, inorganic solid with a definite structure and composition where atoms are arranged in a repeating pattern! Inorganic - not made by or composed of living things! Crystalline - a solid in which the atoms are arranged in a repeating pattern 3

4 Minerals 4

5 Minerals Minerals form by three methods: 1. Crystallization - a process of organizing atoms to form crystalline solids 2. Recrystallization - the cooling and hardening of lava or magma into mineral 3. Rearrangement - the realignment of atoms in minerals under high temperature and pressure 5

6 Minerals! Most rock forming minerals are silicates that result in a tetrahedron shape! Four-sided units of 4 oxygens and 1 silicon 6

7 Minerals! Crystal structure or internal arrangement of atoms are responsible for the physical and chemical properties a mineral possesses 7

8 Internal Arrangement of Adams 8

9 Minerals 9

10 Minerals! Each mineral has a set of physical and chemical properties that can be used to identify the sample! The methods we use to classify minerals are: 10

11 Minerals Color! Color - a visual attribute of an object based on perception! One of the most obvious, but not the most reliable! Many of the 4000 known minerals share similar colors 11

12 Minerals Smokey Quartz Quartz Rose Quartz 12

13 Minerals Streak! Streak - the color of finely crushed powder when a mineral is dragged across a streak plate! Weathering changes the outside color, but streak gives the true color 13

14 Minerals Luster! Luster - the shine of an unweathered mineral or the way it looks in reflected light! Two types of luster: 1.Metallic Luster - shines like stainless steel 2.Nonmetallic Luster - earthy or dull shine 14

15 Minerals Luster Metallic Nonmetallic 15

16 Metallic Luster 16

17 Minerals Density! Density - the ratio of mass and volume of an object M D V 17

18 Minerals Density! Sample Problem: a student measures the mass of a mineral to be 350 g and calculates the volume to be 35 ml. What is the density? D M V 18

19 Minerals Hardness! Hardness - resistance of a mineral to be scratched! Mohs Hardness Scale is used to classify hardness 19

20 Minerals Hardness Mineral Test 1 Talc Finger nail scratches easily 2 Gypsum Finger nail scratches 3 Calcite Copper penny scratches 4 Fluorite Steel knife scratches easily 5 Apatite Steel knife scratches 6 Feldspar Steel knife will not scratches 7 Quartz Will scratch glass and steel 8 Topaz Harder then any common mineral 9 Corundum Scratches topaz 10 Diamond Hardest mineral 20

21 Minerals Cleavage! Cleavage - the tendency of a mineral to break along zones of weakness and form semi-smooth or parallel surfaces 21

22 Minerals Cleavage Mica Halite 22

23 Minerals Cleavage One direction Three directions at 90º 23

24 Minerals Fracture! Fracture - an irregular or uneven break! Tends to lack preferred zones of weakness 24

25 Minerals Fracture Fibrous Conchodial 25

26 Minerals Acid Test! Acid Test - when dilute acid (HCl) is placed on a mineral it can bubble! Calcite and Dolomite both react with acid 26

27 Reaction to Acid 27

28 Mineral Identification 28

29 Igneous Rocks How do we classify igneous rocks? 29

30 Igneous Rocks! Igneous Rocks - rock type that forms when molten material solidifies! Methods to classify igneous rocks: 30

31 Igneous Rocks Environment of Formation! Environment of Formation - the location where liquid rock solidifies into solid rock 31

32 Liquid Hot Magma 32

33 Igneous Rocks Environment of Formation! Magma - molten rock that is inside of the Earth! Plutonic - rock that formed deep within the Earth! Intrusive - below Earth s crust 33

34 Magma Intrusive Environment of Formation 34

35 Igneous Rocks Environment of Formation! Lava - molten rock that is outside of the Earth! Volcanic - rock that formed on the Earth s surface! Extrusive - above Earth s crust 35

36 Lava Extrusive Environment of Formation 36

37 Igneous Rocks Color! Color - for igneous rocks color is broken into two categories of light or dark Dark Light 37

38 Igneous Rocks Composition! Composition - a mixture of materials that make up an igneous rock 38

39 Igneous Rocks Composition! Felsic - light colored rocks that have a high aluminum (Al) content and silicon (Si) Granite Rhyolite 39

40 Igneous Rocks Composition! Maﬁc - dark colored rocks that have a high iron (Fe) or magnesium (Mg) content Scoria Basalt 40

41 Igneous Rocks Texture! Texture - the appearance or character of a rock! Vesicular - texture that consists of gas pockets that give the appearance of having holes! Porphyritic - texture that contains large crystals in a fine grained matrix 41

42 Igneous Rocks Vesicular Porphyritic 42

43 Igneous Rocks Crystal Size! Crystal Size - refers to an actual measurement of the individual crystals or aggregate Obsidian Granite 43

44 Igneous Rocks Crystal Size! Crystal size is an important factor to determine the environment of formation! The longer the cooling time the larger the crystal size (coarse or very coarse)! The shorter the cooling time the smaller the crystal size (glassy or fine) 44

45 Igneous Rocks Coarse Texture Long Cooling Fine Texture Short Cooling 45

46 Earth Science Reference Tables 46

47 Igneous Rocks 47

48 Sedimentary Rocks How do we classify sedimentary rocks? 48

49 Sedimentary Rocks! Sedimentary Rocks - rock type that forms from an accumulation of sediment derived from preexisting rocks and or organic material! Lithification - how sedimentary rocks form! Methods to classify sedimentary rocks: 49

50 Sedimentary Rocks Texture! Texture - the size, form, and orientation of the clasts or pieces in a rock! Texture is the main factor in sedimentary rock identification 50

51 Sedimentary Rocks Texture! Clastic - rock that formed from the fragments or pieces of other rocks and can be identified by size 51

52 Sedimentary Rocks Texture! Crystalline - rock that formed from mineral grains that fall out of solution by evaporation Rock Gypsum Rock Salt 52

53 Sedimentary Rocks Texture! Bioclastic - rock that formed from the remains of plants and animals Coal Limestone 53

54 Sedimentary Rocks Conglomerate Rounded Fragments Breccia Angular Fragments 54

55 Sedimentary Rocks Formation! Formation - how the clasts of a sedimentary rock are held together! Most sedimentary rocks form under large bodies of water by the following: 55

56 Sedimentary Rocks Formation! Cementation - often clasts such as clays, sands, and silts are glued together! Occurs as water between sediments dissolve and the remaining material hold the clasts together 56

57 Sedimentary Rocks Cemented Fragments Cemented Fragments 57

58 Sedimentary Rocks Formation! Compaction - a reduction in volume of sedimentary layers due to increasing weight of overlying sediment! Usually results in a decrease in pore space and sediments becoming more tightly packed 58

59 Sedimentary Rocks Sandstone Sandstone (magnified) 59

60 Sedimentary Rocks Formation! Chemical Action - a rock formed when dissolved minerals in water form a crystalline mass of ingrown mineral crystals after evaporating 60

61 Sedimentary Rocks Salt Flats, Utah Rock Salt 61

62 Sedimentary Rocks Characteristics! Characteristics - the properties and traits that may help identify a sedimentary rock 62

63 Sedimentary Rocks Characteristics! Form at or near Earth s surface where weathering can break down rocks into pieces 63

64 Sedimentary Rocks! Forms in horizontal layers Characteristics 64

65 Sedimentary Rocks! May contain fossils Characteristics 65

66 Earth Science Reference Tables 66

67 Sedimentary Rocks 67

68 Metamorphic Rocks How do we classify metamorphic rocks? 68

69 Metamorphic Rocks! Metamorphic Rocks - parent rocks that have been altered by increases in temperature and pressure! Parent Rock - preexisting rock from which metamorphic rocks are formed 69

70 Metamorphic Rocks Heat! Rock expands when heated causing the atoms to break apart and move freely! As temperature decreases atoms join with other atoms to form different compounds! The result is a structural and chemical change 70

71 Metamorphic Rocks Pressure! Under extreme pressure at great depths inside the Earth, atoms bonds are broken and rearranged into a denser and more compact structure 71

72 Metamorphic Rocks Pressure 72

73 Metamorphic Rocks! Methods to classify metamorphic rocks: 73

74 Metamorphic Rocks Texture! Texture - the general appearance of the rock! Foliation - when minerals rearrange in flat layers due to extreme pressure! Banding - type of foliation where pressure separates minerals into alternating light and dark layers 74

75 Metamorphic Rocks Foliation Slate Foliation with Banding Gneiss 75

76 Metamorphic Rocks Texture! Non-foliated - when minerals rearrange and change form, but do not form layers 76

77 Metamorphic Rocks Non-foliated Marble Non-foliated Quartzite 77

78 Metamorphic Rocks Grain Size! Grain Size - size of the individual grains in the rock Medium Grained Schist Coarse Grained Metaconglomerate 78

79 Metamorphic Rocks Composition! Composition - the minerals that make up the rock Composition: Calcite Rock: Marble Composition: Mica Rock: Slate 79

80 Metamorphic Rocks Type of Metamorphism! Regional Metamorphism - process in which metamorphic rocks are formed over large areas due to temperature and pressure increases! Most metamorphic rocks form regionally under a mountain or deep inside the Earth 80

81 Metamorphic Rocks Type of Metamorphism! Contact Metamorphism - process in which preexisting rock changes when heat from magma or lava rearranges the minerals 81

82 Contact Metamorphism Environment of Formation 82

83 Earth Science Reference Tables 83

84 Metamorphic Rocks 84

85 The Rock Cycle What is the rock cycle and how do rocks interrelate? 85

86 86

87 The Rock Cycle 87

88 The Rock Cycle! Rock Cycle - model that is used to show how the different rock types are interrelated and the processes that create them 88

89 The Rock Cycle! Any rock type can change into another rock type! Therefore any rock could contain materials that were once part of another rock 89

90 The Rock Cycle 90

91 The Rock Cycle! Igneous - formed from melting and solidification! Sedimentary - formed from fragments held together by cementation, compaction, or chemical action! Metamorphic - formed from heat and/or pressure 91

92 The Rock Cycle! Driving Forces - the processes that create uplift, weathering, erosion, pressure, and melting to form the different rock types 1. Earth s Interior 2. Insolation from the Sun 3. Gravity 92

93 The Rock Cycle 93

UNIT TOPICS TOPIC 1: MINERALS TOPIC 2: IGNEOUS ROCKS TOPIC 3: SEDIMENTARY ROCKS TOPIC 4: METAMORPHIC ROCKS TOPIC 5: THE ROCK CYCLE

UNIT TOPICS TOPIC 1: MINERALS TOPIC 2: IGNEOUS ROCKS TOPIC 3: SEDIMENTARY ROCKS TOPIC 4: METAMORPHIC ROCKS TOPIC 5: THE ROCK CYCLE TOPIC 1: MINERALS ESSENTIAL QUESTION: WHAT ARE MINERALS AND HOW DO WE