2. All Minerals 1.Are formed by naturallly 2.Are NOT alive (inorganic) 3.Are solid 4.Are elements or compounds with a unique chemical makeup 5.Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)

3. Rock Forming Minerals Common minerals that make up the Earth’s crust

4. Groups of Minerals Minerals are grouped by the elements they are made of.Minerals are grouped by the elements they are made of. Amethyst Beryl (Emerald) Calcite

5. Mineral Group CharacteristicsExamples Silicates Contain oxygen & silicaContain oxygen & silica The most abundant group of mineralsThe most abundant group of minerals Quartz, mica MICA Quartz

6. Mineral Group CharacteristicsExamples Non-Silicates Make up only 5% of the Earth’s crustMake up only 5% of the Earth’s crust Include some of the most important mineralsInclude some of the most important minerals iron, copper, gold, silver, diamonds, rubies Silver Gold Ruby Iron Copper Diamond

7. Mineral Group CharacteristicsExamples Carbonates Carbon & oxygen and a positive ion, such as calciumCarbon & oxygen and a positive ion, such as calcium Calcite (CaCO 3 ) Calcite with Duftite inclusions

8. Mineral Group CharacteristicsExamples Oxides  Metallic ion and oxygen Hematite (Fe 2 )O 3

9. Mineral Group CharacteristicsExamples Sulfides  Sulfur and a metallic ion Galena (PbS)

10. Mineral Group CharacteristicsExamples Sulfates  Metallic ion, Sulfur & oxygen Barite (BaSO 4 ) Barite on Calcite BaSo4 / CaCO3 Barite BaSo4

11. Mineral Group CharacteristicsExamples Native Elements  Single elements Gold (Au), Diamond (C), Silver (Ag)

12. How do minerals form? 1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle))1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle)) –Fast Cooling = No Crystals (mineraloids) –Medium Cooling = small crystals –Slow Cooling = large crystals

13. How do minerals form? 2) Elements dissolved in liquids (water)2) Elements dissolved in liquids (water)

14. Physical Properties of Minerals (can be used to identify the mineral) Color Can be misleadingCan be misleading Can vary with the type of impuritiesCan vary with the type of impurities

15. Physical Properties of Minerals (can be used to identify the mineral) Luster Surface reflectionSurface reflection metallic = shiny like metalmetallic = shiny like metal non-metallic = dull, non-shiny surfacenon-metallic = dull, non-shiny surface Pyrite has a metallic luster Calcite has a non-metallic luster

16. Physical Properties of Minerals (can be used to identify the mineral) Streak The color of the powdered form of the mineralThe color of the powdered form of the mineral The color of the streak can be different than the mineralThe color of the streak can be different than the mineral Minerals must be softer than the streak plateMinerals must be softer than the streak plate

17. Physical Properties of Minerals (can be used to identify the mineral) Hardness How easily a mineral scratches materialsHow easily a mineral scratches materials Mohs Hardness ScaleMohs Hardness Scale Scale from 1 (softest) to 10 (hardest)Scale from 1 (softest) to 10 (hardest) Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)Test by seeing if the mineral can scratch different objects (like human fingernail, copper, penny, glass, steel file)

18. Physical Properties of Minerals (can be used to identify the mineral) Cleavage & Fracture –The way the mineral breaks –Cleavage—minerals break along smooth, flat surfaces and every fragment has the same general shape –Fracture—minerals that break at random with rough or jagged edges

20. Cleavage or Fracture? 1. 3. 2. 4.

21. Physical Properties of Minerals (can be used to identify the mineral) Other Properties –Specific gravity = dry mass mass lost in water mass lost in water –Attraction to magnets –Reaction with hydrochloric acid –Smell & taste

22. Definition of a Mineral “A naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal crystal structure.”

24. Mineral Characteristics Chemical composition –Diamond = graphite (both are pure carbon) Crystal structure –Diamond ≠ graphite

25. Halite Crystal Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

26. Galena Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

27. Fluorite Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

28. Halite Source: Photograph © The McGraw-Hill Companies, Inc./Doug Sherman, photographer.

29. Cubic Structure of Halite Source: Photograph © The McGraw-Hill Companies, Inc./Bob Coyle, photographer.

30. Mineral Properties Hardness (Mohs hardness scale) –See appendix C Cleavage (how it breaks- atomic scale) Luster- the surface ‘sheen’ Color is not a good property for i.d. –Corundum (Al 2 O 3 )

31. Minerals: two groups Silicates (Si + O ± other elements) –All built with ‘silicon tetrahedra’ –4 O atoms, 1 Si atom, 4 - charge –Quartz, feldspars –Olivine (peridot) ferromagnesian (Fe, Mg) –Asbestos –Micas –Clays (tropical weathering)

32. Minerals: non-silicates NonsilicatesExample –Carbonates (CO 3 ): calcite –Sulfates (SO 4 ): gypsum –Sulfides (metal + S): pyrite –Oxides (metal + O): hematite –Hydroxides (metal + OH): gibbsite –Halides (metal + halide): salt (halite) –Native elements Au, Ag, Pt, Cu, C

33. Labradorite has labradorescence or chatoyance. LABRADORITE

34. A. FELDSPARS (two varieties to identify) All have two directions of cleavage. 2. ORTHOCLASE (pink, tan or white) KAlSi 3 0 8 Has stringers that go through the mineral - looks superficially like striations. Look at display so that you know what striations are. ORTHOCLASE

35. B. FERROMAGNESIANS (iron and magnesium silicates) All have two directions of cleavage. 1. AMPHIBOLES (2 types to identify) Cleavage planes intersect forming 124 o and 56 o cleavage angles. Crystals usually long and thin. a. HORNBLENDE (black) Cleavage Angles

36. A. FELDSPARS (two varieties to identify) All have two directions of cleavage. 1. PLAGIOCLASE (2 types to identify) (Ca,Na)(Si,Al) 4 O 8 Have striations on cleavage planes (end at edge of cleavage plane). a. OLIGOCLASE (white) Na-rich feldspar b. LABRADORITE (gray to black) Ca-rich feldspar LABRADORITEOLIGOCLASE STRIATIONS

37. b. ACTINOLITE (greenish gray or grayish green) Crystals usually in radiating masses (check with me if not visible!) ACTINOLITE

38. 2. PYROXENES (1 to identify) Cleavage planes intersect forming 88 o and 92 o cleavage angles. Crystals usually short and stubby. a. AUGITE (greenish black) AUGITE

39. C. MICAS (3 to identify) All have one direction of cleavage, producing platy appearance. 1. MUSCOVITE (white-silver) 2. BIOTITE (brown) 3. CHLORITE (green) - may not look like the other micas in terms of plateyness. Chlorite

40. D.QUARTZ (SiO 2 ) Hardness is 7. Can be many colors due to impurities. Displays conchoidal fracture. ROSE QUARTZAMETHYST

41. CONCHOIDAL FRACTURE

42. E. OLIVINE Olivine is olive green. Granular appearance. May be able to see conchoidal fracture of grains with hand lens.

43. F. CALCITE (CaCO 3 ) Fizzes or effervesces in HCl. Three directions of cleavage not at right angles (rhombohedral cleavage). Clear pieces may exhibit double refraction. RHOMBOHEDRAL CLEAVAGE HCl ACID REACTION

44. DOUBLE REFRACTION

45. G. GARNET Reddish-brown color (but can be others). Has hackly fracture, no cleavage. Roundish crystals with 12-24 flat faces readily visible in most cases.

46. H. STAUROLITE Crystals usually twinned ("fairy crosses").

47. Mineral appearance color color (not very useful) Pyrite Gold

48. Mohs Hardness Scale Mineral Talc Gypsum Calcite Fluorite Apatite Feldspar Quartz Topaz Corundum Diamond Rating 1Softest known mineral. It flakes easily when scratched by a fingernail. 2A fingernail can easily scratch it. 3A fingernail cannot scratch it, but a copper penny can. 4A steel knife can easily scratch it. 5A steel knife can scratch it. 6Cannot be scratched by a steel knife, but it can scratch window glass. 7Can scratch steel and hard glass easily. 8Can scratch quartz. 9Can scratch topaz. 10Hardest known mineral. Diamond can scratch all other substances. Testing Method Hardness

49. Luster The way a mineral reflects a light luster. metallicnonmetallicEither metallic or nonmetallic

50. Specific Gravity comparedThe specific gravity of a mineral is the ration of its weight compared with the weight of an equal volume of water. 19Gold has specific gravity of 19 19 times heavierIt means gold is 19 times heavier than water. 19 times heavier

51. Specific Gravity

52. Streak When a mineral is rubbed across a piece of porcelain tile a streak of powdered mineral is left behind.

53. Cleavage Cleavage is the way that mineral breaks. Minerals that break along smooth, flat surfaces have cleavage. Mica has cleavage

54. Fracture Mineral that breaks uneven, rough, or jagged surfaces have fracture. Quartz has fracture quartz

55. Identify the minerals below for cleavage and fracture CLEAVAGEFRACTURE

56. Uncut and cut Diamonds (C)

57. Some examples of minerals… This is pyrite (FeS 2 ), also known as “Fool’s Gold.”

58. Common Mineral... Crystal QuartzMilky Quartz (SiO 2 )

59. This is also a variety of quartz (a rarer gem variety). SiO 2, + Fe and Mn (that reflects purple light) Rare Mineral...

60. Another Rare Mineral Mica (lepidolite) that has a purplish appearance.

61. Gemstones: emerald tourmaline sapphire ruby sapphire

62. Chemical Composition unique chemical composition Each mineral has a unique chemical composition which makes it different from all other minerals. Examples:CopperCu GoldAu HaliteNaCl QuartzSiO 2 CalciteCaCO 3 CorundumAl 2 O 3 BerylBe 3 Al 2 Si 6 O 18 RubyAl 2 O 3 DiamondC

63. Minerals Have a Crystal Structure In addition to a unique chemical composition, each mineral has a definite structure. Crystal structure: the repeating pattern of how the atoms in the mineral are bonded together. When a mineral forms, it can show this overall crystal structure.

64. Crystal Forms of Carbon These are eight different crystal forms of carbon: diamond, graphite, lonsdaleite, C60, C540, C70, amorphous carbon and a carbon nanotube

65. Minerals Silicates are by far the most abundant mineral group accounting for more than 90% of the Earth's crust. Silicates are the major rock-forming minerals. It follows that oxygen and silicon are the most abundant elements in the crust.

66. There are many ways in which the SiO4 tetrahedra can be assembled to build neutral silicate mineral structures. Isolated tetrahedra balanced by the cations magnesium (Mg), iron (Fe),calcium (Ca) –Olivines (Mg, Fe) 2 SiO 4, Magnesium Iron SilicateOlivines –and GarnetsGarnets Minerals

67. The typical pyroxene structure contains chains of SiO 3 tetrahedrons The slope of the tetrahedral pyramids helps to determine the cleavage angle of the pyroxenes at nearly 90 o degrees (actually 93 o and 87 o ).

68. Minerals common amphiboles: Actinolite Ca 2 (Mg, Fe +2 ) 5 Si 8 O 22 (OH) 2 Anthophyllite (Mg, Fe) 7 Si 8 O 22 (OH) 2 Arfvedsonite Na 3 (Fe +2 ) 4 Fe +3 Si 8 O 22 (OH) 2 Cummingtonite Mg 7 Si 8 O 22 (OH) 2 Edenite NaCa 2 Mg 5 Si 8 O 22 (OH) 2 Fluorrichterite Na(CaNa)Mg 5 Si 8 O 22 F 2 Glaucophane Na 2 (Mg 3 Al 2 ) Si 8 O 22 (OH) 2 The Hornblende Series Ca 2 (Mg, Fe +2 ) 4 (Al, Fe +3 )Si 7 AlO 22 (OH) 2 Double chains of tetrahedra balanced by similar cations.

69. Minerals Micas and Clay MineralsMicas Sheets of tetrahedra are the building blocks. Aluminum is also involved in these sheet structures which are charge-balanced by the cations Mg, Na and K. most common mica minerals: muscovite, biotitemuscovite biotite

70. Minerals Feldspars A second group of alumino- silicates, tetrahedra form three- dimensional frameworks with Ca, Na and K as the balancing cations. The very abundant feldspar are subdivided in K-Na bearing alkali feldspars and the Ca-Na solid-solution series called plagioclase feldspars. The K-feldspars or alkali felspars: Microcline, (Potassium aluminum silicate)Microcline Sanidine, (Potassium sodium aluminum silicate)Sanidine Orthoclase, (Potassium aluminum silicate)Orthoclase

71. Minerals Feldspars A second group of alumino- silicates, tetrahedra form three- dimensional frameworks with Ca, Na and K as the balancing cations. The very abundant feldspar are subdivided in K-Na bearing alkali feldspars and the Ca-Na solid-solution series called plagioclase feldspars. The plagioclase feldspars: Albite, (Sodium aluminum silicate)Albite Oligoclase, (Sodium calcium aluminum silicate)Oligoclase Andesine, (Sodium calcium aluminum silicate)Andesine Labradorite, (Calcium sodium aluminum silicate)Labradorite Bytownite, (Calcium sodium aluminum silicate)Bytownite Anorthite, (Calcium aluminum silicate)Anorthite

72. Minerals Quartz Silica tetrahedra alone can form a neutral three- dimensional framework structure with no need for other cations. This arrangement forms a very stable structure popular as ornamental stone and as gemstones Amethyst is the purple gemstone variety.Amethyst Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.Citrine Milky Quartz is the cloudy white variety.Milky Quartz Rock crystal is the clear variety that is also used as a gemstone.Rock crystal Rose quartz is a pink to reddish pink variety.Rose quartz Smoky quartz is the brown to gray variety.Smoky quartz

73. Minerals Quartz SiO4Quartz Silica tetrahedra alone can form a neutral three- dimensional framework structure with no need for other cations. This arrangement forms a very stable structure popular as ornamental stone and as gemstones Amethyst is the purple gemstone variety.Amethyst Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.Citrine Milky Quartz is the cloudy white variety.Milky Quartz Rock crystal is the clear variety that is also used as a gemstone.Rock crystal Rose quartz is a pink to reddish pink variety.Rose quartz Smoky quartz is the brown to gray variety.Smoky quartz

74. Minerals Quartz Silica tetrahedra alone can form a neutral three- dimensional framework structure with no need for other cations. This arrangement forms a very stable structure popular as ornamental stone and as gemstones Amethyst is the purple gemstone variety.Amethyst Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.Citrine Milky Quartz is the cloudy white variety.Milky Quartz Rock crystal is the clear variety that is also used as a gemstone.Rock crystal Rose quartz is a pink to reddish pink variety.Rose quartz Smoky quartz is the brown to gray variety.Smoky quartz

75. Minerals Quartz Silica tetrahedra alone can form a neutral three- dimensional framework structure with no need for other cations. This arrangement forms a very stable structure popular as ornamental stone and as gemstones Amethyst is the purple gemstone variety.Amethyst Citrine is a yellow to orange gemstone variety that is rare in nature but is often created by heating Amethyst.Citrine Milky Quartz is the cloudy white variety.Milky Quartz Rock crystal is the clear variety that is also used as a gemstone.Rock crystal Rose quartz is a pink to reddish pink variety.Rose quartz Smoky quartz is the brown to gray variety.Smoky quartz

76. Non-silicates: Carbonates: CO 3Carbonates The important carbonates are the minerals calcite and dolomite. Both are significant rock-forming minerals. The Calcite Group:Calcite Group: Calcite (Calcium Carbonate)Calcite Gaspeite (Nickel Magnesium Iron Carbonate)Gaspeite Magnesite (Magnesium Carbonate)Magnesite Otavite (Cadmium Carbonate)Otavite Rhodochrosite (Manganese Carbonate)Rhodochrosite Siderite (Iron Carbonate)Siderite Smithsonite (Zinc Carbonate)Smithsonite Sphaerocobaltite (Cobalt Carbonate)Sphaerocobaltite Minerals

77. Non-silicates: Evaporites: halides including the minerals halite, sylvite and fluorite; sulphates including the minerals gypsum and anhydrite. halides sulphates Most famous halide mineral, halite (NaCl) or rock salt

78. Minerals Non-silicates: Evaporites: halides including the minerals halite, sylvite and fluorite; sulphates including the minerals gypsum and anhydrite. halides sulphates Fluorite: CaF2, Calcium Fluoride

79. Minerals Non-silicates: Evaporites: halides including the minerals halite, sylvite and fluorite; sulphates including the minerals gypsum and anhydrite. halides sulphates Gypsum:CaSO4-2(H2O), Hydrated Calcium Sulfate

80. Minerals Non-silicates: Oxides oxides (hematite and magnetite) Fe2O3, Iron Oxide hydroxides (limonite and goerthite) important minor consituents in rocks. aluminum oxide bauxite can also occur as a rock-forming mineral. oxide minerals are exploited as economic sources of many elements including aluminum, antimony, iron, manganese, tin, and uranium.

81. Minerals Non-silicates: Oxides oxides (hematite and magnetite) Fe3O4, Iron Oxide hydroxides (limonite and goerthite) important minor consituents in rocks. aluminum oxide bauxite can also occur as a rock-forming mineral. oxide minerals are exploited as economic sources of many elements including aluminum, antimony, iron, manganese, tin, and uranium.

82. Minerals Non-silicates: Sulphides The mineral pyrite is the only sulphide that occurs commonly in rocks. Sulphides are most important as economic minerals providing the main sources of elements such as arsenic, copper, lead, nickel, mercury, molybdenum and zinc. FeS2, Iron Sulfide

83. Minerals Non-silicates: Sulphides The mineral pyrite is the only sulphide that occurs commonly in rocks. Sulphides are most important as economic minerals providing the main sources of elements such as arsenic, copper, lead, nickel, mercury, molybdenum and zinc. PbS, Lead Sulfide, Galena

84. Minerals Non-silicates: Sulphides The mineral pyrite is the only sulphide that occurs commonly in rocks. Sulphides are most important as economic minerals providing the main sources of elements such as arsenic, copper, lead, nickel, mercury, molybdenum and zinc. CuFeS2, Copper Iron Sulfide, Chalcopyrite

85. Minerals Non-silicates: Phosphates are relatively rare. The only important phosphate mineral is apatite. Ca2Fe(PO4)2 - 4H2O, Hydrated Calcium Iron Phosphate

86. Crystal System ISOMETRIC DIAMOND TETRAGONAL WULFENITE HEXAGONAL BERYL TRIGONAL QUARTZ variety - AMETHYST ORTHORHOMBIC TANZANITE MONOCLINIC GYPSUM TRICLINIC MONTEBRASITE AMORPHOUS AMBER

87. Crystal System SEVEN CRYSTALLOGRAPHIC SYSTEMS: 1.ISOMETRIC, requires 4 three fold axis of rotation. ISOMETRIC 2.TETRAGONAL, requires 1 four fold axis of rotation. TETRAGONAL 3.HEXAGONAL, requires 1 six fold axis of rotation. HEXAGONAL 4.TRIGONAL, requires 1 three fold axis of rotation. TRIGONAL 5.ORTHORHOMBIC, requires either 3 two fold axis of rotation or 1 two fold axis of rotation and two mirror planes. ORTHORHOMBIC 6.MONOCLINIC, requires either 1 two fold axis of rotation or 1 mirror plane. MONOCLINIC 7.TRICLINIC, requires either a center or only translational symmetry. AMORPHOUS; no symmetry is present and it is therefore not a crystallographic system.TRICLINIC

88. Common Minerals the most common minerals you'll find in rocks ”rock forming minerals” These contain plagioclase feldspar, potassium feldspar, quartz, muscovite mica, biotite mica, amphibole, olivine, and calcite.plagioclase feldsparpotassium feldsparquartz muscovite micabiotite micaamphiboleolivinecalcite

89. Minerals Dr. R. B. Schultz

90. The earth is made of rocks… and rock are made of minerals. Minerals are: · 1. Naturally occurring, · 2. Inorganic, · 3. Have known chemical compositions · 4. Have definite physical properties. 5. Are solid · They are usually crystalline.

91. Mineral Classification Minerals are classified based on chemical composition and crystal structure. Minerals are made of different ions bonded together. Ions are charged atoms  Cations are + charged  Anions are - charged Common ions in earth's crust: O - most common ion (anion) Si, Al, Fe, Ca, Na, K, Mg, (Cations) Minerals are made mainly of these ions Crystal structure Crystal structure depends on sizes of and charges on ions Polymorphs -- same chemical composition, different crystal structures Mafic silicate minerals Most common minerals are silicates All silicate minerals contain silicon and oxygen Silicates that also contains iron or magnesium are called mafic silicate minerals Mafic silicate minerals are dark in color Examples: of mafic silicates: olivine, pyroxene, amphibole, and biotite mica Felsic silicates Felsic silicates are silicate minerals that don't contain magnesium or iron, are light in color Examples: feldspar, quartz, clay minerals, muscovite mica Silicate mineral structures Basic building block: silica tetrahedron Silica tetrahedron is a silicon ion bonded to 4 oxygen ions Silicon is positively charged (+4) Oxygen is negatively charged (-2) Net charge on tetrahedron: -4 Because tetrahedron is negatively charged, it is attracted to cations Tetrahedra may link together by a cation (e.g. Mg, Fe, Na, Ca, K) serving as a bridge, or Tetrahedra may link together by sharing oxygens Isolated tetrahedral structure Cations serve as links between tetrahedra; no sharing of oxygens e.g. olivine, and garnet, which also happen to be mafic silicates Single chain silicates Adjacent tetrahedra form a chain by sharing 2 of their oxygens with neighboring tetrahedra e.g. pyroxenes, which also happen to be mafic silicates Double chain silicates Two chains can link up by sharing oxygens e.g. amphiboles, which are mafic silicates too Sheet silicates Sheets are formed when each tetrahedron shares 3 of its oxygens with its neighbors e.g. micas, biotite (mafic) and muscovite (non- mafic), and clay minerals, which are non-mafic silicates Framework silicates Every oxygen in each tetrahedron is shared to form 3-D framework e.g. feldspar, quartz, which are also non-mafic Common non-silicate minerals Calcite -- calcium carbonate -- Limestone is made of calcite. Dolomite -- calcium magnesium carbonate Gypsum -- calcium sulfate Galena -- lead sulfide Pyrite -- iron sulfide Halite -- sodium chloride (table salt) How to Identify Minerals: Physical Properties Geologists determine the identity of an unknown mineral by describing its physical properties. They then use a reference book to find out what mineral has those properties. We will learn to describe the physical properties. 1. Habit refers to the overall shape of the mineral use terms like: "equant" (3 dimensions of the mineral have about the same length, like a cube or sphere), “elongate" (one direction is long but the other 2 are short, like a pencil), or "platy" (one dimension is short, other 2 are long like a sheet of paper) isolated tetrahedra & framework silicate minerals tend to be equant in habit; chain silicates tend to be elongate, sheet silicates are platy 2. Cleavage Refers to very smooth, flat, shiny breakage surfaces These special breakage surfaces correspond to zones of weak bonding in the crystal structure To describe cleavage, must determine the number of unique cleavage planes (directions) and their angle with respect to each other (e.g. salt breaks into cubes, with cleavage in 3 directions, all at 90 degrees) 3. Hardness Refers to "scratchability" of the minerals harder minerals will scratch softer minerals Rank minerals according to hardness using the Moh's scale Fingernails are about 2.5 on Moh's scale; glass or steel knife is about 5.5; use these common items to estimate hardness of a mineral. 4. Color Varies in many minerals, e.g. quartz Some minerals come in just one color; other are many colors/many varieties 5. Streak Refers to color of mark left by rubbing mineral against a streak plate (unglazed porcelain) streak does not vary even if color does. 6. Other Properties Some minerals are magnetic Some minerals effervesce ("fizz") in dilute acid Specific gravity (like density) Moh's Hardness Scale (Commit this to memory) 1.0 TALC 2.0 GYPSUM 2.5 FINGERNAIL 3.0 CALCITE 3.5 COPPER PENNY 4.0 FLUORITE 5.0 APATITE 5.5 STEEL KNIFE BLADE/GLASS PLATE 6.0 ORTHOCLASE FELDSPAR 7.0 QUARTZ 8.0 TOPAZ 9.0 CORUNDUM (RUBY) 10 DIAMOND

92. Crystal structure depends on sizes of and charges on ions Most common mineral group is the silicates All silicate minerals contain silicon and oxygen 1. Mafic silicate minerals contain iron or magnesium and are dark in color. Examples: olivine, pyroxene, amphibole, and biotite mica 2. Felsic silicates don't contain magnesium or iron, and are light in color. Examples: feldspar, quartz, clay minerals, muscovite mica

93. Mafic silicate Felsic silicate

94. Silica Tetrahedron OxygensSilicon

96. Common non-silicate minerals Fluorite – used as a toothpaste additive Calcite -- calcium carbonate -- Limestone is made of calcite. Dolomite -- calcium magnesium carbonate Gypsum -- calcium sulfate Galena -- lead sulfide Pyrite -- iron sulfide Halite -- sodium chloride (table salt)

97. Non-Metallic Mineral Metallic Mineral Luster the way a mineral reflects

98. Cleavage Refers to very smooth, flat, shiny breakage surfaces These special breakage surfaces correspond to zones of weak bonding in the crystal structure. To describe cleavage, one must determine the number of unique cleavage planes (directions) NO Cleavage

99. Hardness Refers to "scratchability" or resistance to being scratched. Harder minerals will scratch softer minerals. Geologists rank minerals according to hardness using the Moh's scale 1.0 TALC 2.0 GYPSUM 2.5 FINGERNAIL 3.0 CALCITE 3.5 COPPER PENNY 4.0 FLUORITE (Note the spelling!) 5.0 APATITE 5.5 STEEL KNIFE BLADE/GLASS PLATE 6.0 ORTHOCLASE FELDSPAR 7.0 QUARTZ 8.0 TOPAZ 9.0 CORUNDUM (RUBY) 10.0 DIAMOND

100. Color Varies in many minerals, e.g. quartz VERY unreliable. Some minerals come in just one color; other are many colors/many varieties. Streak Refers to color of mark left by rubbing mineral against a streak plate (unglazed porcelain). Streak does not vary even if color does. Other Properties Some minerals are magnetic (i.e., magnetite) Some minerals effervesce ("fizz") in dilute acid (calcite) Specific gravity (like density) galena-high specific gravity.