Mineralogy -II

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Mineralogy -II

  1. 1. Mineralogy
  2. 2. Rock Forming Minerals • Only few minerals form the great bulk of the rock of the crust of the earth. These very common minerals have been grouped to- geather as rock forming minerals. • Among the rock forming minerals, Three groups like Silicates, Oxides and Carbonates are considered as these three groups include most of the common rock forming minerals.
  3. 3. The Silicate Group • About eight percent of the crest of the earth is made of silicates and free silica. Among the silicate group, the total number of minerals known to occur in nature may easily approach to about one thousand species. Since majority of them are quite rare in occurrence. Since this group of minerals is one of the biggest a little knowledge of the important aspect of the group such as Chemical Composition, Atomic Structure, Classification and descriptive study of some important minerals.
  4. 4. The Silicate Group Chemical Composition • Most common silicate minerals are made up chiefly of a few of the following nine elements, Na, K, Al, Ca, Mg, Fe, Li, Si, and O. Other elements are present only rarely and in traces.
  5. 5. The Silicate Group Atomic Structure • The fundamental unit. All silicates are simple or complex repetition of a fundamental Silicon-Oxygen Tetrahedron, represented by the formula [ SiO 4] 4-. In this tetrahedron, the very small Si 4- ion is situated in the centre and is surrounded on the four sides by relatively big oxygen ions. The dimensions. The dimension of this unit cell of silicon- oxygen tetrahedron are constant. Further, the distance between the silicon ion at the centre and the oxygen atom at the corner is 106 A0 . This fundamental unit is repeated, linked and joined in different ways giving rise to different types of silicate structures.
  6. 6. The Silicate Group
  7. 7. The Silicate Group
  8. 8. The Silicate Group Independent Tetrahydra. A unit SiO4 has four negative charges. Hence it has the capacity to exist as an isolated or independent tetrahydron provided these four negative charges are balanced by four positive ions of other metals. This actually happens in nature in orthosilicates. Sometimes more than one elements may combine with an independent tetrahydon to satisfy the four negative valency giving rise to different types of minerals.
  9. 9. Independent Tetrahydra.
  10. 10. The Silicate Group Double Linked Tetrahedra • In Some cases SiO4- may first get linked together in such a way that one oxygen atom is held common between the two cells. The net negative charge left in two joint tetrahedral is 6 (O-Si-O-Si-O) and the formula for such tetrahydron is (Si2O7)6-. In fact it is known as Si2O7 group. Complexed-linked Tetrahedron. • In some cases, three, four and six tethedron may be linked together in such a way that they form closed ring-type structures.
  11. 11. The Silicate Group
  12. 12. The Silicate Group The Chain Structure • It results from single-dimensional continuation in which each tetrahedron is linked to the adjacent tetrahedron by sharing the two corners. This is the characteristic structure of Pyroxene group of silicates and is commonly referred as single-chain structure. • A double chain structure is also possible according to formula • [ Si4 O11]6- The amphibole group of minerals has this type of double- chain extension. • These will have six, eight and twelve free negative charges to be satisfied • The formula is expressed as • [Si3O9]6-, [Si4O12]8-, and [ Si6O18]12- • Repetition in space The single tetrahedron and the double linked tetrahedron as described above may in themselves be repeted in space in a variety of ways giving rise to different structural forms in the silicate minerals.
  13. 13. The Silicate Group
  14. 14. The Silicate Group
  15. 15. The Silicate Group
  16. 16. The Silicate Group The Sheet Structure • A two-dimensional continuation of silicon tetrahedron commonly result in a layered or sheet structure. It is characterized by linking of the tetrahedrons in such a way that all the three apexes of one tetrahedron are linked with an adjoining tetrahedron resulting ultimately into hexagonal pattern lengthwise, and breadthwise. • Such sheets may be linked with other identical sheets resting above or below through metallic ions resulting in a considerable weaker bond.
  17. 17. The Silicate Group
  18. 18. The Silicate Group
  19. 19. The Silicate Group The Network Structure • In this type of structure, the silicon- oxygen tetrahedron are so arranged that they form a three dimensional network.
  20. 20. The Silicate Group
  21. 21. Crystal System
  22. 22. The Felspar Group • The felspar group are the most prominent group of minerals making more than fifty percent by weight, crust of the earth up to a depth of 30 km. These occur chiefly in the igneous rocks but also form a good proportion of their metamorphic derivatives.
  23. 23. The Felspar Group Chemical Composition • In Chemical Composition, felspar are chiefly aluminosilicates of Na, K and Ca with the chemical formula: • WZ4O8 • In which W= Na, K, Ca and Ba • And Z= Si and Al • The Si:Al shows variation from 3:1 to 1:1. Some examples of minerals are • NaAlSi3O8 • KalSiO3O8 • CaAl2SiO2O8
  24. 24. The Felspar Group Atomic Structure • At atomic level, the felspars shows a continuous three-dimensional network type of structure in which the SiO4 tetrahedra are linked at all four corners, each oxygen ion being shared by two adjacent tetrahedron • The resulting network is negatively charged and these negative charges are satisfied by the presence of positively charged K, Na, Ca and also Ba.
  25. 25. The Felspar Group Orthoclase Plagioclase K-feldspar Ca/Na-feldspar
  26. 26. The Felspar Group Crystallization • The felspar group of minerals crystallographic systems: monoclynic and triclinic. • Infact the plagioclase of felspar crystallizes only in Triclinic system.
  27. 27. The Felspar Group Felspar are classified both as on the basis of their chemical composition and also on their mode of crystallization. Chemically felspar group fall into two main group the potash felspar and soda lime felspar Potash Felspar • Orthoclase • Sandine • Microline Soda lime Felspar • Albite • Labradorite • Oligoclase • Bywonite • Andesine • Anorthite
  28. 28. The Felspar Group Physical Properties • In addition to their close relationship in chemical composition, crystallography and atomic constitution, felspar group of minerals exhibit a broadly similarity and closeness in their physical character as well so that differentiation of one variety from other requires very through, sometimes microscopic examination. • They are general light in color, have lower specific gravity and have a double cleavage and a hardness varying between 6-6.5.
  29. 29. Orthoclase Physical Properties of Orthoclase • Cleavage: {001} Perfect, {010} Good • Color: Colourless, Greenish, Greyish yellow, White, Pink. • Density: 2.56 • Diaphaneity: Transparent to Translucent • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars). • Habit: Massive - Granular - Common texture observed in granite and other igneous rock. • Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). • Hardness: 6 – Orthoclase • Luminescence: Non-fluorescent. • Lustre: Vitreous (Glassy) • Streak: White
  30. 30. Orthoclase
  31. 31. Microcline Physical Properties of Microcline • Cleavage: {001} Perfect, {010} Good • Color: Bluish green, Green, Gray, Greyish yellow, Yellowish. • Density: 2.56 • Diaphaneity: Translucent to transparent • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars). • Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals. • Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). • Hardness: 6 – Orthoclase • Luminescence: Fluorescent, Short UV=cherry red. • Lustre: Vitreous (Glassy) • Streak: White
  32. 32. Microcline
  33. 33. Albite Physical Properties of Albite • Cleavage: {001} Perfect, {010} Good • Color: White, Gray, Greenish gray, Bluish green, Gray. • Density: 2.61 - 2.63, Average = 2.62 • Diaphaneity: Transparent to translucent to sub translucent • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars). • Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix. • Habit: Striated - Parallel lines on crystal surface or cleavage face. • Hardness: 7 - Quartz • Luminescence: Fluorescent, Short UV=herry-red blue, Long UV=white. • Lustre: Vitreous (Glassy) • Streak: White
  34. 34. Albite
  35. 35. Anorthite Physical Properties of Anorthite • Cleavage: {001} Perfect, {010} Good • Color: Colourless, Gray, White, Red, Reddish gray. • Density: 2.72 - 2.75, Average = 2.73 • Diaphaneity: Transparent to Sub transparent to translucent • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form. • Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix. • Habit: Striated - Parallel lines on crystal surface or cleavage face. • Hardness: 6 – Orthoclase • Luminescence: Non-fluorescent. • Lustre: Vitreous (Glassy) • Streak: White
  36. 36. Anorthite
  37. 37. Anorthite
  38. 38. The Felspar Group • Crystographically, Felspar fall into two crystal systems Monoclinic Felspar • Orthoclase • Sandine Triclinic Felspar • Microclinic • Albite-Anorthite
  39. 39. Orthoclase
  40. 40. Pyroxene Group • The pyroxene group of minerals forms another set of important rock-forming minerals. They occur in good abundance in the dark colored igneous and metamorphic rocks. In fact among the ferro-magnesium minerals, pyroxenes occupy first place as rock forming group.
  41. 41. Pyroxene
  42. 42. Pyroxene Group Chemical Composition • In Chemical Composition, Pyroxenes are essentially ferro-mangnesium silicates, with other bases as calcium, sodium, aluminum and lithium being also present in varying amount in different varieties. • In the simplest form, the chemical composition of pyroxenes may be represented as RSiO3 with R representing Ca, Na and Al and li etc.
  43. 43. Pyroxene Group Atomic Structure • The pyroxene show the single-chain structure of silicates. In this type of constitution, the fundamental silicon-oxygen tetrahedron are linked together at one of the oxygen atoms. In other words, one oxygen atom is shared between two adjacent SiO4 giving rise to typical prismatic cleavage of the group.
  44. 44. Pyroxene Group Crystallization • Pyroxenes in two systems: Orthorhombic and Monoclinic. The prism angle in pyroxenes are 870 and 930 and form a distinct features of Pyroxenes.
  45. 45. Pyroxene Group • Pyroxenes care commonly classified on the basis of their crystallization in two groups • Orthorhombic Pyroxenes • Enstatite • Hyperstene • Monoclinic Pyroxenes • Clinoenstatite • Clinohypersthene • Diopside • Augite • Acmite • Spodumene
  46. 46. Pyroxene Group Physical Properties • They are generally dark in color, their hardness varies between 5 to 6 and sp gravity from 3 to 3.3. Pyroxene crystal are generally short and stout.
  47. 47. Enstatite Physical Properties of Enstatite • Cleavage: { 110} Distinct, {010} Distinct • Color: White, Yellowish green, Brown, Greenish white, Gray. • Density: 3.1 - 3.3, Average = 3.2 • Diaphaneity: Translucent to opaque • Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals. • Habit: Lamellar - Thin laminate producing a lamellar structure. • Habit: Massive - Fibrous - Distinctly fibrous fine-grained forms. • Hardness: 5.5 - Knife Blade • Luminescence: Non-fluorescent. • Lustre: Vitreous - Pearly • Streak: Gray
  48. 48. Enstatite
  49. 49. Hypersthene Physical Properties of Hypersthene • Cleavage:{100} Perfect, {010} Perfect • Color: Greyish white, Greenish white, Yellowish white, Bronzy brown, Greyish black. • Density:3.2 - 3.9, Average = 3.55 • Diaphaneity: Translucent to transparent • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals. • Habit: Massive - Granular - Common texture observed in granite and other igneous rock. • Hardness:5.5-6 - Knife Blade-Orthoclase • Luminescence:Non-fluorescent. • Luster:Vitreous - Silky • Streak:grayish greenish white
  50. 50. Hypersthene
  51. 51. Diopside Physical Properties of Diopside • Cleavage: {110} Good, Indistinct • Color: Blue, Brown, Colourless, Green, Gray. • Density: 3.25 - 3.55, Average = 3.4 • Diaphaneity: Transparent to translucent • Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. • Habit: Blocky - Crystal shape tends to be equant (e.g. feldspars). • Habit:Granular - Generally occurs as anhedral to subhedral crystals in matrix. • Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). • Hardness: 6 - Orthoclase • Luminescence: Non-fluorescent. • Lustre: Vitreous (Glassy) • Streak: White green
  52. 52. Diopside
  53. 53. Augite • Physical Properties of Augite • Cleavage: {110} Perfect, {010} Indistinct • Color: Brown green, Green, Light brown, Dark brown, Black. • Density: 3.2 - 3.6, Average = 3.4 • Diaphaneity: Translucent to opaque • Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. • Habit: Columnar - Forms columns • Habit: Granular - Generally occurs as anhedral to subhedral crystals in matrix. • Habit: Massive - Fibrous - Distinctly fibrous fine-grained forms. • Hardness: 5-6.5 • Luminescence: Non-fluorescent. • Lustre: Vitreous - Resinous • Streak: Greenish gray
  54. 54. Augite
  55. 55. Amphibole Group • This group of minerals is regarded as a parallel to the pyroxene group because most minerals of this group shows a striking resemblance to the pyroxene minerals in many of their properties. They are also characterized with a double cleavage, a hardness between 5-6 and sp gravity from 3 to 3.5 they are generally dark in color.
  56. 56. Amphibole
  57. 57. Amphibole Group Chemical Composition • Amphibole minerals are also metasilicates with Si : O ratio of 4: 11. The Metallic ions present in amphiboles in amphiboles are Ca, Mg, Fe and sometimes Mn, Na , K and H. Presence of (OH) ion, which may be replaced by F and Cl, is another peculiarly of chemical composition. The general chemicals formula: • [Si4 O11]2 [OH]2, forms the basis for combination with the metallic ions. There is possibility of a good degree of substitution between various ion such as Al, Mg, Fe, Ca, Na and K, H and F and So on giving rise to a variety of amphibole minerals.
  58. 58. Amphibole Group Atomic Structure • There is a basic difference in the atomic constitution of pyroxenes and amphiboles the SiO4 tetrahedra are linked in double chain; it is for this reason that the amphiboles are more complex in their chemical constitution.
  59. 59. Amphibole Group Crystallization • More important members of amphiboles group crystallize in two crystal system • Orthorhombic and Monoclinic The amphibole crystal are generally long, slender and prismatic; these sometimes fibrous in habit, the prism angle in amphibole is 124 0
  60. 60. Amphibole Group • Amphiboles are commonly divided in two groups on the basis of their crystallization • Orthorhombic amphiboles and monoclinic amphiboles.
  61. 61. Amphibole Group • Despite wide variation in their chemical composition, amphiboles show quite few common physical characters due to their atomic structures. Thus all of them crystallize in only two crystal systems. • Physical Properties • Most of them are dark in color have a hardness ranging between 5-6 and Sp Gr. Between 2.8 to 3.6. Their crystal are elongated, slender and often fibrous in nature.
  62. 62. Anthophyllite • Physical Properties of Anthophyllite • Cleavage: {110} Perfect, Distinct, Distinct • Color: White, Greenish gray, Green, Clove brown, Brownish green. • Density: 2.85 - 3.57, Average = 3.21 • Diaphaneity: Transparent to translucent • Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). • Habit: Fibrous - Crystals made up of fibers. • Habit: Lamellar - Thin laminate producing a lamellar structure. • Habit: Massive - Uniformly indistinguishable crystals forming large masses. • Hardness: 5-6 - Between Apatite and Orthoclase • Luminescence: Fluorescent, Short UV=red, Long UV=red. • Lustre: Vitreous - Pearly • Streak: Gray
  63. 63. Anthophyllite
  64. 64. Tremolite Physical Properties of Tremolite • Cleavage:{110} Perfect, {010} Distinct • Color: Brown, Colourless, Gray, White, Light green. • Density:2 .9 - 3.2, Average = 3.05 • Diaphaneity: Transparent to translucent • Fracture: Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces. • Habit: Columnar - Forms columns • Habit: Massive - Fibrous - Distinctly fibrous fine-grained forms. • Habit: Massive - Granular - Common texture observed in granite and other igneous rock. • Hardness: 5-6 - Between Apatite and Orthoclase • Luminescence: Fluorescent, Short UV=yellow, Long UV=range pink. • Lustre: Vitreous - Pearly • Streak: White
  65. 65. Tremolite
  66. 66. Actinolite Physical Properties of Actinolite • Cleavage: {110} Perfect, {110} Perfect • Color: Green, Green black, Gray green, Black. • Density: 2.98 - 3.1, Average = 3.04 • Diaphaneity: Translucent to transparent • Fracture: Splintery - Thin, elongated fractures produced by intersecting good cleavages or partings (e.g. hornblende). • Habit: Bladed - Aggregates of thin lath-like crystals (e.g. kyanite). • Habit: Fibrous - Crystals made up of fibers. • Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite) • Hardness: 5.5 - Knife Blade • Luminescence: Non-fluorescent. • Lustre: Vitreous (Glassy) • Streak: White
  67. 67. Actinolite
  68. 68. Hornblende • Physical Properties of Hornblende • Color usually black, dark green, dark brown • Streak white, colourless (brittle, often leaves cleavage debris behind instead of a streak) • Lustre vitreous • Diaphaneity translucent to nearly opaque • Cleavage two directions intersecting at 124 and 56 degrees • Mohs Hardness 5 – 6 • Specific Gravity 2.9 - 3.5 (varies depending upon composition) • Diagnostic Characteristics Cleavage, color, elongate habit • Crystal System monoclinic
  69. 69. Hornblende
  70. 70. Mica Group • Minerals of Mica Group are characterized with the presence of a micaeous structure (Cleavage) by virtue of which these can be split into very thin sheets along one direction. This micaceous cleavages is explained by their atomic constitution they consist of SiO4 tetrahedra linked at three of their corner and extending in two dimensions. This is called Sheet structures. • Micas are besides feldspar, pyroxenes and amphiboles, very common rock forming minerals forming approximately 4 % of the crest of the earth.
  71. 71. Mica Group
  72. 72. Mica Group Chemical Composition • Mica group of minerals show a great variation in their chemical composition. Broadly speaking they are mainly silicates of aluminum and potassium containing one or more of • Hydroxyl group • Sodium • Magnesium • Lithium • Iron • Fluorine
  73. 73. Mica Group Atomic Structure • As mentioned above, micas are characterized with sheet structure in atomic constitution. In this type of structure, the basic unit of silicates, SiO4 tetra hydra lined at all their three corners resulting in Si :O ratio of 2:5 Such a linkage when extended in two directions results in Sheet of SiO2-tetrahedra.
  74. 74. Mica Group Crystallization • Most important member of mica Group crystallize in one system only: Monoclinic System some less important members crystallize in Triclinic System.
  75. 75. Mica Group • Micas are generally divided into two group based on their chemical composition Light Micas • Muscovite • Paragonite • Lepidolite Dark Micas • Biotite • Phlogopite • Zinwaldite
  76. 76. Mica Group Physical Properties • Among the properties that are common to all the minerals of the mica group are • Perfect basal cleavage • Low hardness between 2-3 • Viterous lusture • Platy habit of the crystal
  77. 77. Muscovite Physical Properties of Muscovite • Cleavage:{001} Perfect • Color:White, Gray, Silver white, Brownish white, Greenish white. • Density:2.77 - 2.88, Average = 2.82 • Diaphaneity:Transparent to translucent • Fracture:Brittle - Sectile - Brittle fracture with slightly sectile shavings possible. • Habit:Foliated - Two dimensional platy forms. • Habit: Massive - Lamellar - Distinctly foliated fine-grained forms. • Habit:Micaceous - Platy texture with "flexible" plates. • Hardness:2-2.5 - Gypsum-Finger Nail • Luminescence:Non-fluorescent. • Luster:Vitreous (Glassy) • Streak:white
  78. 78. Muscovite
  79. 79. Biotite Physical Properties of Biotite • Cleavage: {001} Perfect • Color: Dark brown, Greenish brown, Blackish brown, Yellow, White. • Density:2.8 - 3.4, Average = 3.09 • Diaphaneity: Transparent to translucent to opaque • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Lamellar - Thin laminate producing a lamellar structure. • Habit: Micaceous - Platy texture with "flexible" plates. • Habit: Pseudo Hexagonal - Crystals show a hexagonal outline. • Hardness: 2.5-3 - Finger Nail-Calcite • Luminescence: Non-fluorescent. • Lustre: Vitreous - Pearly • Streak: Gray
  80. 80. Biotite
  81. 81. Biotite
  82. 82. Oxide Minerals • Next to silicate minerals, oxide occupy an important positions in the list of rock forming minerals. Some of them are important as non- metallic refrectory minerals (e.g. Quartz, coroundum, spinel, and rutile) Many others are very important as Source minerals of metals such as hematite, magnetite(iron), cuperite (copper), Zincite (zinc), cassiterite (tin) and bauxite (aluminum).
  83. 83. Oxide Minerals Quartz (SiO2) • Polymorphous Transformation (Polymorphism is the ability of a solid material to exist in more than one form or crystal structure.) • Quartz, when heated, transforms into high temperature modified as follows • Quartz ------ Tridymite ------ Critobalite -------- Melt • The variety named as Quartz itself as two polymorphs • α Quartz • β Quartz • Identification of exact type of minerals requires through investigation of the mode of formation. 870 0C 1470 0C 1713 0C
  84. 84. Quartz (SiO2)
  85. 85. Oxide Minerals • Right handed and left handed Quartz • When occurring in distinct crystal, quartz may be distinguished into right handed and left handed types This is done on the basis of recognition of some typical faces such as trigonal, trapezohedron and dipyramid. This two faces normally occur at the edges of prism faces, one above another. • In the left handed quartz, these faces are located on the left side of the upper edge of the prism whereas in the right-handed quartz, these occur on the right upper edge of the crystal.
  86. 86. Right handed and left handed Quartz
  87. 87. Oxide Minerals Coloured Varieties • Common pure quartz is a colorless transparent mineral. Presence of even a trace of an impurity may give it a characteristics color and hence a variety. A few common types of quartz are • Amethyst: Purple or White • Smoky : Dark to light brown, even black • Milky: Pure white or opaque • Rose Red: Coloured is attributed to presence of titanium.
  88. 88. Oxide Minerals Crystocrystalline Types • In many cases, crystallization of pure silica to quartz remains incomplete due to interruption in the process for one reason to another. Silica occurring in this cryptocrystalline varieties, altogether close in composition and physical properties to quartz is named directly. • A few variety of cryptocrystalline silica are • Chalcedony, Agate, Onyx, Flint, Jasper • Occurrence Quartz and its variety occur in all types of rocks; Igneous, sedimentary and metamorphic. In igneous rocks, quartz makes up the bulk of acidic varieties. In sedimentary rocks quartz makes up sandstone and ortho quartzite. Loose sand consists mostly of quartz grains. The metamorphic rocks like gneisses and schists contain good proportion of quartz in some cases.
  89. 89. Quartz Physical Properties of Quartz • Cleavage: {0110} Indistinct • Color: Brown, Colourless, Violet, Gray, Yellow. • Density: 2.6 - 2.65, Average = 2.62 • Diaphaneity: Transparent • Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz). • Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals. • Habit: Crystalline - Fine - Occurs as well-formed fine sized crystals. • Habit: Druse - Crystal growth in a cavity which results in numerous crystal tipped surfaces. • Hardness: 7 - Quartz • Luminescence: Fluorescent and Triboluminescent, Short UV=yellow- orange, Long UV=yellow-orange. • Lustre: Vitreous (Glassy) • Streak: white
  90. 90. Quartz
  91. 91. Corundum Physical Properties of Corundum • Cleavage: None • Color: Blue, Red, Yellow, Brown, Gray. • Density: 4 - 4.1, Average = 4.05 • Diaphaneity: Transparent to translucent • Fracture: Tough - Difficult to break apart as shown by fibrous minerals and most metals. • Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form. • Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). • Habit: Tabular - Form dimensions are thin in one direction. • Hardness: 9 – Corundum • Luminescence: Sometimes Fluorescent, Long UV=red. • Lustre: Vitreous (Glassy) • Magnetism: Nonmagnetic • Streak: none
  92. 92. Corundum
  93. 93. Spinel Physical Properties of Spinel • Cleavage: None • Color: Colourless, Red, Blue, Green, Brown. • Density: 3.57 - 3.72, Average = 3.64 • Diaphaneity: Transparent to translucent to opaque • Fracture: Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern. • Habit: Euhedral Crystals - Occurs as well-formed crystals showing good external form. • Habit: Massive - Granular - Common texture observed in granite and other igneous rock. • Hardness: 8 - Topaz • Luminescence: Sometimes Fluorescent, Short UV=red, Long UV=red. • Lustre: Vitreous (Glassy) • Magnetism: Nonmagnetic • Streak: greyish white
  94. 94. Spinel
  95. 95. Carbonate Minerals • A few carbonate minerals are very important as rock forming minerals in sedimentary and metamorphic groups. These include calcite, dolomite and magnetite.
  96. 96. Carbonate Minerals Calcite-Dolomite
  97. 97. Calcite Physical Properties of Calcite • Cleavage: {1011} Perfect, {1011} Perfect, {1011} Perfect • Color: Colourless, White, Pink, Yellow, Brown. • Density:2.71 • Diaphaneity: Transparent to translucent to opaque • Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. • Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals. • Habit: Massive - Uniformly indistinguishable crystals forming large masses. • Habit: Stalactitic - Shaped like pendant columns as stalactites or stalagmites (e.g. calcite). • Hardness: 3 - Calcite • Luminescence: Fluorescent and phosphorescent, Short UV=yellow, blue, red green, Long UV=yellow, blue, red green. • Lustre: Vitreous (Glassy) • Streak: white
  98. 98. Calcite
  99. 99. Calcite Physical Properties of Dolomite • Cleavage: { 1011} Perfect, {1011} Perfect, {1011} Perfect • Color: White, Gray, Reddish white, Brownish white, Gray. • Density: 2.8 - 2.9, Average = 2.84 • Diaphaneity: Transparent to translucent • Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. • Habit: Blocky - Rhombohedral - Crystal shape resembles rhomohedrons. • Habit: Crystalline - Coarse - Occurs as well-formed coarse sized crystals. • Habit: Massive - Uniformly indistinguishable crystals forming large masses. • Hardness: 3.5-4 - Copper Penny-Fluorite • Luminescence: Non-fluorescent. • Lustre: Vitreous (Glassy) • Streak: white
  100. 100. Calcite
  101. 101. Magnesite • Physical Properties of Magnesite • Cleavage: {1011} Perfect, {1011} Perfect, {1011} Perfect • Color: Colourless, White, Greyish white, Yellowish white, Brownish white. • Density: 3 • Diaphaneity: Transparent to translucent to opaque • Fracture: Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments. • Habit: Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite). • Habit: Massive - Fibrous - Distinctly fibrous fine-grained forms. Habit: Massive - Granular - Common texture observed in granite and other igneous rock. • Hardness: 4 - Fluorite • Luminescence: Fluorescent, Short UV=blue white, Long UV=bright blue white. • Lustre: Vitreous (Glassy) • Streak: White
  102. 102. Magnesite
  103. 103. • Engineering and General Geology :by Parbin Singh • Textbook of Engineering Geology :N.Chenna Kesavullu • http://geology.com/ • http://webmineral.com/ • http://www.mindat.org/ • http://www.asu.edu/courses/glg103/PDF%20labs/Lab%202%20Mineral%20L ab%20ID%20revised%2017JULY2010.pdf
  104. 104. Thanks

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