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ROCKS AND Minerals 2013 BY MARY WILDE.

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Presentation on theme: "ROCKS AND Minerals 2013 BY MARY WILDE."— Presentation transcript:

1 ROCKS AND Minerals 2013 BY MARY WILDE

2 Rules & Suggestions TEAM OF 2 TEAMS MAY BRING: MAGNIFYING GLASS
1 PUBLISHED FIELD GUIDE 3-RING BINDER Make review sheets: Examples: formulas for all minerals, physical properties of minerals, uses for minerals REFER TO THE NATIONAL 2013 LIST Official 2012 Rocks and Minerals List (PDF)

3 TEAM PREPARATION NOTEBOOK
Meet once a week, give students a course outline; what you are going to study each week. Give them a short assignment to work on for the next week. Each student composes a notebook. 12X12X3 Give a station whenever possible; time practice, and practice using notebooks. NOTEBOOK

4 VISITATIONS SEE SPECIMEN
VISIT COLLEGES, MINERAL MUSEUMS TO SEE DIFFERENT SPECIMEN. VISIT ROCK AND MINERAL SHOWS WITH STUDENTS; GET THEM HOOKED! SEEK OUT SPECIALISTS, SOME OUR JUST OLD ROCK HOUNDS! GO ON YOUR OWN ROCK & MINERAL HUNT!

5 ELEMENTS!! Periodic Table: Occurrence in minerals Elements & Compounds
Structure of the Table (metals, nonmetals) Elements & Compounds Formulas and Symbols Common Radicals

6 WHAT IS A MINERAL? Inorganic solid Naturally occurring Homogeneous
Definite physical properties Semi- Definite composition Crystalline Structure

7 Why Minerals are important?

8 SIX BASIC TYPES OF MINERAL ENVIRONMENTS
IGNEOUS ENVIRONMENTS (PLUTONIC AND VOLCANIC) METAMORPHIC ENVIRONMENTS SEDIMENTARY ENVIRONMENTS HYDROTHERMAL REPLACEMENT DEPOSITS HYDROTHERMAL VEINS SECONDARY REPLACEMENT DEPOSITS

9 PLUTONIC IGNEOUS ENVIRONMENT

10 PEGMATIC ENVIRONMENTS
Pegmatite minerals include apatite, biotite, corundum, feldspar, muscovite, quartz, pyroxene, topaz, tourmaline.

11 Metamorphic Environments
Some Minerals only form under great heat and pressure and these minerals can become unstable when conditions change. When stability is affected , existing rocks undergo change and new minerals can form.

12 Sedimentary Environments
Placer Deposits: Heavy stable minerals remain behind when rocks disintegrate and these remains are carried by moving water. GOLD!

13

14 Hydrothermal Replacement Minerals
Hydrothermal water, especially acid water, is effective at removing, changing and replacing minerals in the surrounding country rock. Azurite is a secondary copper mineral and develops in the zone of alteration in hydro thermal replacement deposits, where it commonly occurs with malachite.

15 Vein Deposits

16 HYDROTHERMAL VEIN DEPOSITS
PYRITE Fluorite (formed in Ill when hot water flowed through cracks in limestone.

17 Secondary Replacement Deposits
Develop from primary minerals in the original deposit. Chalcopyrite alters readily to Bornite!

18 IDENTIFYING MINERALS COLOR (LEAST RELIABLE)
STREAK: Color of Powdered mineral HARDNESS LUSTER SPECIFIC GRAVITY TENACITY CLEAVAGE/FRACTURE CYRSTAL SYSTEM OTHER PROPERTIES

19 COLOR OF MINERAL Visible light spectrum radiation reflected from a mineral.

20 Amethyst Amazonite Azurite & Malachite Lepidolite

21 STREAK : The color of the powered mineral
Pyroxene Hematite Limonite Magnetite Amphibole Streak color: Colorless Brick red Yellow brown Black

22 MOH’S SCALE OF HARDNESS

23 IDENTIFYING MINERALS LUSTER Metallic or Non metallic
Vitreous Adamantine pearly resinous silky waxy greasy dull

24 SPECIFIC GRAVITY How many more times a mineral weighs compared to an equal amount of water. Specific Gravity = Weight of sample in air/ Weight of equal volume of water Weight of sample in air / loss of weight in water

25 TENACITY How tough a mineral is, how easily it will break or split
* elastic: Can be bent and then resume original shape (mica) * ductile: Pulled to make thin threads. (gold) * malleable: Cut into thin sheets (copper) * Sectile: Can be cut by blade into shavings ( Gypsum) * Friable: crumbles easily

26 Malleable and Ductile Gold Copper

27 OTHER PROPERTIES BIREFRINGENCE : Difference between highest and lowest index of refraction. A high degree causes double refraction.

28 Reaction to Acid Ca Co3 + 2H --- Ca + H2O + CO2
Al Carbonate Minerals, Limestones and marble

29 Magnetic Properties Occurs when there is an imbalance in structural arrangement of the Fe atoms. The Ferrous ion is Fe +2 and the Ferric ion is Fe +3. When the electrons move from the Ferrous to the Ferric ions, a magnetic field is created.

30 Fluorescent Minerals The changing of invisible light or X-ray beams to visible light. If light continues after source is turned off, the mineral is phosphorescence.

31 Piezoelectric Properties
Temperature or pressure changes cause some minerals to acquire an electric charge when warmed, cooled or pressed. Quartz Tourmaline

32 CRYSTALS ARRANGEMENT OF ATOMS

33 HABIT THE CHARACTERISTIC APPEARANCE OF A CRYSTAL. Terms to describe crystal habit are: Prismatic : Beryl Prismatic Terminated Prisms Quartz in Barite

34 Habit Dendritic Copper Reniform (kidney- shaped) Hematite

35 Habit Description TWINNING
Contact Twin Penetration Twin Quartz Staurolite

36 STRIATIONS, PRODUCT OF THE HABIT

37 FRACTURE No Cleavage planes
Hackly Conchoidal irregular

38 Cleavage Examples

39 CLEAVAGE BASAL: 1 direction or planes (layers)
Muscovite, talc Prismatic: 2 directions at rt angles: Barite Cubic: 3 directions at right angles: Halite Rhombohedral: 3 directions: calcite Octahedral: 4 planes (pyramid) Fluorite Dodecahedral: 6 planes Sphalerite

40 What Cleavage? Mineral Mineral Cleavage Cleavage

41 What Cleavage Type? Mineral Mineral Cleavage Cleavage

42 Scientific Classification of Mineral Groups
There are eight major classes according to chemical composition 1. Elements 2. Sulfides 3. Oxides and Hydroxides 4. Halides 5. Nitrates Carbonates Borates 6. Sulfates 7. Phosphates 8. Silicates

43 NATIVE ELEMENTS Six in this Group
Graphite, silver, gold, copper, sulfur, diamond. Occur in nature in uncombined form. Copper Silver Gold Gold METALS: Silver Copper

44 Non Metals Native Elements Graphite, Diamond & Sulfur

45 Sulfide class Metals with sulfur
Economically important class of minerals Major ores of important metals (Cu, Pb, Ag, Fe, Zn) Most are metallic, opaque, sectile, soft to average hardness, and high densities, and igneous in origin There are five in this group All give streaks!

46 SULFIDES Copper Iron Sulfides
BORNITE CHALCOPYRITE

47 SULFIDES PYRITE GALENA SPHALERITE
Iron sulfide Lead sulfide Zinc Sulfide

48 OXIDE CLASS Five in this group
Includes Oxides and Hydroxides 45% of Earth’s crust is Oxygen, very diverse group Quartz (SiO2) could be considered an oxide except for the covalent silicon oxygen bonds. The OH group has a -1, where as the single oxygen has a -2 charge

49 OXIDES Corundum Hematite Magnetite
Aluminum Oxide Iron Oxide Iron Oxide

50 HYDROXIDES Bauxite Goethite Aluminum Hydroxide Iron Hydroxide

51 HALIDES (Two in this group)
Commonly found as a metal and a halogen (the principle anion) Halite (NaCl) Fluorite (CaF2)

52 CARBONATES Contain one or more metallic elements plus the carbonate radical (CO3) Soft, brittle, transparent, effervesce in HCl, soft with good to perfect cleavage Tend to originate in sedimentary and oxidizing environments Three major types are calcites, aragonites and dolomites

53 Aragonite, a polymorph of calcite
Dolomite, CaMg(CO3)2

54 Azurite and Malachite: Copper Carbonates
Malachite represents a later stage of oxidation an replaces azurite.

55 BORATES, More complex than Carbonates Metal Plus Borate Radical
Ulexite, Evaporite Deposit

56 SULFATE CLASS One or more metallic elements plus the Sulfate radical, SO4 Transparent to translucent, soft, most are heavy and light colored Includes Barite, Celestite, and Gypsum Variety of environments, Often in oxidation zones and evaporite deposits

57 SULFATES Many have economic Importance
BARITE BaSO4 CELESTITE, SrSO4

58 GYPSUM: several variety names.
Selenite Satin Spar Alabastor

59 PHOSPHATES One or more metal elements with the phosphate radical, PO4
Apatite in Calcite

60 SILICATES SIO4 40% OF COMMON MINERALS ARE SILICATES!

61 SIX CLASSES OF SILICATES Low SG, Harder than most minerals
Based on the interactive formations of the tetrahedrons 1. Tectosilicates Framework Silicates 2. Phyllosilicates Sheer Silicates 3. Inosilicates Chain Silicates 4. Cyclosilicates Ring Silicates 5. Sorosilicates Double Tetrahedral 6. Neosilicates Independent Tetrahedral

62 TECTOSILICATES SIO2 GREEK FOR FRAMEWORK! Every
O atom is bonded to two Si atoms as in Crystal Quartz Opal

63 Quartz Family Rose Quartz Agate Amethyst
Chalcedony Jasper Milky Quartz Citrine Quartz

64 TECTOSILICATES SIO2 + FELDSPARS
A negative charge is created, which introduces the positive metals of K, Na or Ca. Sodalite

65 PHYLLOSILICATES Clay Group
Greek for leaf, sheet silicates (have one cleavage direction parallel to layers) KAOLINITE TALC

66 Phyllosilicates (Micas)
MUSCOVITE MICA Lepidolite

67 INOSILICATES Inosilicates: the chain structure, double or single.
Amphibole Group: Wedge shaped prismatic cleavage planes; longer, slender crystals. Hornblende Tremolite Rhodonite

68 INOSILICATES, Pyroxene Group
Prismatic cleavage planes give it a square or rectangular cross section. Shorter and more blocky crystals as compared to amphiboles. AUGITE

69 CYCLOSILICATES Beryl and Tourmaline
Greek for ring, known as the ring Silicates!The symmetry of the rings gives these two minerals the hexagonal shape!

70 SOROSILICATES Have two tetrahedrons linked by one oxygen giving it an hour glass shape Epidote: Metamorphic Environment

71 Neosilicates Isolated Tetrahedron: Garnet, Olivine, Topaz, Staurolite (short, blocky, square crystals) Garnet Olivine TOPAZ Staurolite Greek for Island, share no oxygen ions.

72 IGNEOUS ROCKS CLASSIFIED BY TEXTURE AND MINERAL COMPOSITION
REFERRED TO AS INTRUSIVE(PLUTONIC) OR EXTRUSIVE (VOLCANIC) FORM FROM FELSIC MINERALS (LIGHT COLORED, ACIDIC) OR MAFIC MINERALS (DARK COLORED, BASIC)

73 TEXTURE OF IGNEOUS ROCKS
PHANERITIC: Intrusive, coarse grained. Granite Diorite Gabbro Felsic Intermediate Mafic

74 Fine Grained Igneous Rocks
Aphanitic Texture (Extrusive) Rhyolite Andesite Basalt Felsic Intermediate Mafic

75 Glassy or Frothy Texture
Pumice Obsidian Scoria Frothy Glassy Frothy Felsic Felsic Mafic

76 PEGMATITE Abnormally large crystals. Unlike other igneous rocks that develop from the molten state, pegmatites grow from aqueous solutions. Pegmatites can produce large crystals in a short period of time. (geologically)

77 Porphyritic Texture Two distinct crystal sizes produced by different cooling of the liquid rock. The large crystals are called phenocrysts. Porphyritic rhyolite Porphyritic basalt

78 SEDIMENTARY ROCKS CLASSIFIED AS CLASTIC OR NONCLASTIC.
CLASTIC: SEDIMENTS CEMENTED OR COMPACTED TOGETHER NONCLASTIC: ORGANIC, OR CHEMICALPRECIPITATES.

79 Sedimentary Rock Features
Graded Bedding and Cross Bedding

80 Sedimentary Rocks: Ripple Marks and Mudcracks

81 SEDIMENTARY ROCKS AND FOSSILS
Shale with Fossils Fossiliferous Limestone Coal with Fossils

82 SORTING OF SEDIMENTS

83 ORGANIC ORIGIN Bio-chemical
Coquina Chalk Fossiliferous limestone

84 CLASTIC ROCKS Classified by texture or grain size
Conglomerate Breccia Gravel size range (over 2mm) Rounded Fragments Angular Fragments

85 Clastic Rocks: Sand size Range (1/16 mm to 2mm)
Sandstone Arkose Mostly quartz At least 25% feldspar

86 Clastic rocks: Clay size particles less than 1/256 mm
Shale: laminated layers of quartz and clay minerals

87 Coal Formation Peat exposed to heat and pressure from burial beneath other sediments becomes compressed and chemically changes into low grade coals such as this lignite. Lignite typically transforms to bituminous coal as it is compressed further and heated to between 100 and 200°C. This drives much of the water and other volatiles from the coal. Longer exposure to elevated temperature will further drive volatiles from the coal, and drive chemical reactions that produce anthracite.

88 The carbon content of the coal rises as it is compressed further and the moisture content falls.

89 Organic Origin: Coal Lignite Bituminous Anthracite

90 Organic Origin: Diatomite
Diatomaceous earth, the pinkish white outcrop shown above (near Lovelock, Nevada), is a mineral of plant origin. It represents the accumulation of an enormous number of fossil diatoms (single-celled plants Diatomite has several unique characteristics. Because of its lightness, porosity, and its honeycombed structure, it's an ideal filtering medium.

91 Chemical Limestones When Minerals fall out of solution
Crystalline Oolitic Travertine Dolomite limestone limestone Rock

92 AGENTS OF METAMORPHISM
HEAT: Geothermal gradient: due to radioactive decay and intrusions of hot magma. Pressure: Burial Pressure, Tectonic Pressure, or fault zones pressure. Chemical fluids: hydrothermal solutions

93 HOW ROCKS CHANGE TEXTURE: Compaction: more dense, less porous
* MINERALOGY Recrystallization: Growth of new crystals from Minerals present, often forming foliation.

94 METAMORPHIC TEXTURES SCHISTOSITY: large mica flakes
Slaty cleavage: alignment of very fine grained micas. Phyllitic structure: alignment of fine grained micas. Gneissic banding: segregation of light and dark minerals into layers.

95 METAMORPHIC ROCKS TYPES
CONTACT METAMORPHISM: MAGMA FORCES ITS WAY INTO OVERLYING ROCK, CHANGING THE ROCKS THAT COME IN CONTACT WITH IT. CHANGES ARE LESS DRASTIC AND FOLIATION NOT PRESENT. REGIONAL METAMORPHISM: LARGE AREAS OF ROCK UNDERGO INTENSE HEAT AND PRESSURE. (OCCURS DURING MOUNTAING BUILDING PROCESSES) Often foliation!

96 KINDS OF METAMORPHISM

97 REGIONAL METAMORPHISM “Barrovian”
Slate------phyllite schist------gneiss

98 Contact Metamorphism (Not always by contact)
Marble Quartzite

99 ROCK CYCLE

100


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