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NON-SILICATES
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Non Silicates Native Elements 1. metals 2. semi metals 3. non metals
minerals comprised of atoms of only one element 1. metals minerals with high heat and electrical conductance, malleability, ductility and a strong metallic bond Au, Ag, Cu, Pt, etc. 2. semi metals minerals with lesser conductivity but more brittle than metals and consist of a mixture of metallic and covalent bond types Sb, Bi and As 3. non metals minerals which are non conductors, are very brittle and soft and have a covalent type of bond C (graphite), S (sulfur)
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Sulfides, Arsenides, Sulfarsenides
minerals with strong metallic bond type with a general formula, AmXp, where X is S or As, Sb, Bi and Te and A represents one or more metals sulfides--S is the only major anion arsenides--As takes the place of S totally ( NiAs) sulfarsenides—semimetals take place of S in part (FeAsS) many of these minerals are known as “primary minerals” or those formed from hydrothermal solutions with no oxidation during formation examples are: chalcocite—resembles enargite but has no cleavage bornite—peacock ore—displays a tarnish and can resemble covellite but does not have cleavage galena –very high specific gravity with cubic cleavage and the only source of lead
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sphalerite comprised of Fe and Zn resinous to adamantine yellowish to deep red(ruby ore) to black(jack) indicating a progressively higher Fe content used as a geothermal mineral—the higher the Fe content, the higher the temperature of formation most important ore of Zn and an important source of Cd leaves a rotten egg smell when rubbed on a porcelain scratch plate chalcopyrite distinguished from pyrite in that it has no cleavage and is softer than glass distinguished from millerite in that it has no radiating crystal habit distinguished from pyrrhotite in that it is not magnetic “ “ marcasite in that it has no cockscomb structure
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pyrrhotite magnetic caused by omission solid solution and a defect structure caused by an Fe deficiency with respect to S in the formula niccoline (niccolite) red-brass colored with a high specific gravity millerite hair like radiating crystal habit pentlandite resembles pyrrhotite but not magnetic principle ore of Ni covellite also known as peacock ore, with special iridescence excellent cleavage resembling that of mica indigo color
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cinnabar red, high specific gravity with prominent cleavage most important ore of Hg realgar red and associated with orpiment orpiment yellow and distinguished from S by its prominent cleavage pyrite harder than chalcopyrite occurs often in cubic cleavage form with striations most common sulfide minerals commonly known as fool’s gold marcasite a polymorph with pyrite differs from pyrite by the presence of the cockscomb structure
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molybdenite distinguished from graphite by a higher specific gravity and more bluish tone principal ore of Mo arsenopyrite distinguished from marcasite by its somewhat silver-white color principal source of As
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Sulfosalts Oxides an example is: examples are:
have general formula, AmBnXp where A can be Ag, Cu, Pb and B can be As, Sb,Bi and X is S the semimetals act as cations in the sulfosalts as compared to anions in the sulfarsenides and arsenides an example is: enargite distinguished from chalcocite by its prominent cleavage Oxides bond type is primarily ionic which results in part to a greater hardness displayed by these compared to others previously discussed examples are: cuprite in various shades of red
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Hematite group examples are: zincite
red and occurs often with franklinite Hematite group isostructural group—6 O bonded to each cation and 4 anions bonded to each cation (e.v. of bond = ½) examples are: corundum hardness = 9 sapphires (blue) and rubies (red) are important gem stone varieties hematite occurs often as oolitic hematite (non metallic luster) or specularite or massive hematite (both metallic luster) most important ore of iron ilmenite distingushed from magnetite from lack of strong magnetism The major source of Ti
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Rutile group examples are:
isostructural group with 6 O around each cation and 3 cations around each O examples are: rutile much lower S.G. than cassiterite adamantine luster and reddish color pyrolustite low hardness and leaves a black streak on paper most important Mn ore cassiterite very high S.G. principal ore of Sn
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Spinel group examples are:
isostructural group—first cation in formula is +2 and second is +3 examples are: magnetite very magnetic chromite massive to granular distinguished from magnetite by lack of magnetism the only abundant ore of Cr franklinite distinguished from magnetite by lack of strong magnetism is abundantly associated with zincite
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Hydroxides examples are: brucite
distinguished from talc by a greater hardness and lack of a strong greasy feel manganite distinguished from pyrolusite and other black mineral by its brown streak often occurs in prismatic crystals romanechite (psilomelane) black and occurs often in botryoidal form goethite black and often oxidizes to limonite (yellow) bauxite recognized by its pisolitic form—most important ore of Al
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Halides examples are: consists of minerals with a halogen anion halite
distinguished by its cubic cleavage and salty taste which is less bitter than taste of sylvite cryolite fluorite often found in cubes and in various colors has distinct octahedral cleavage is an important source of F in the production of HF
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Carbonates Calcite group examples are:
The remaining non silicate classes are comprised of minerals each combined with a meso-or aniso and isodesmic bond Calcite group isostructural group 6 O around each major cation, 3 O around C and 1 C and 2 other major cations around each O examples are: calcite prominent rhombohedral cleavage and often found as rhombohedron or scalenohedron(dog tooth) forms distinguished from other minerals by strong effervescence with cold HCl in a solid non powered form magnesite prominent rhombohedral cleavage but rare and usually white and very fine grained
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Aragonite group siderite
prominent rhombohedral cleavage with curved faces distinguished from other carbonates by its light to dark brown color and from sphalerite by its type of cleavage and lack of smell of rotten eggs on a streak plate rhodochrosite prominent rhombohedral cleavage with curved faces and pink color smithsonite blue-green in color and botryoidal or stalactitic in form Aragonite group isostructural group with 9 Oaround each major cation, 3 O around each C, and 1 C and 3 major cations around each O
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Dolomite group example is: aragonite polymorphic with calcite
distinguished from calcite by the lack of rhombohedral cleavage and from witherite and strontionate by its much lower S.G. witherite high S.G. distinguished from barite by its effervescence in cold HCl in powered form Dolomite group isostructural group similar to the calcite group example is: dolomite often displays curved rhombohedral cleavage effervesces in HCl in power form only
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Borates Hydrous Carbonate group examples are: malachite
distinguished by its bright green color and botryoidal form effervesces with cold dilute HCl yeilding a green solution azurite distinguished by its azure blue color and effervescence with cold HCl yielding a blue solution Borates there is a polmerization of the basic structural units as in the silicates because of the presence of the mesodesmic bond borates are the source of borax and B
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examples are: kernite characterized by its long splintery cleavage fragments and slow solubility in cold water can resemble gypsum but is harder and cannot be scratched by the fingernail borax characterized by its crystals and its low hardness resulting in powdery form easily soluble in cold water colemanite commonly found in short prismatic crystals
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Sulfates Barite group an example is:
isostructural group with 12 O around each major cation, 4 O around each S, and 1 S and 3 major cations around each O an example is: barite distinguished by its prominent cleavage, high S.G. and often by the special crystal forms as bladed barite, clear barite, rose barite and a black barite chief source of Ba anhydrite not isostructural with barite---8 O around each Ca, 4 O around each S and 1 S and only 2 Ca around each O 2 directional 90 degree cleavage
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Tungstates Hydrous Sulfate group examples are: an example is: gypsum
characterized by its low hardness (2) and 3 cleavage directions can occur in several forms as bladed gypsum, selenite (clear), satin spar and massive or alabaster alunite Tungstates wolframite group is an isostructural group an example is: wolframite distinguished from other minerals by its black color, one directional cleavage and high S.G. an important ore of W
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Molybdates Vanadates Phosphates an example is: examples are: wulfenite
characterized by its orange-yellow color, high S.G. and tabular (tetragonal) crystals Vanadates vanadinite characterized by its ruby red to orange red color, resinous luster and high S.G. Phosphates examples are: monazite rare earth phosphate with high S.G. and main source of Th and other rare earth elements
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apatite green, red and yellow apatite are varieties amblygonite distinguished from sodic plagioclase by the lack of striations wavelite commonly in radiating crystal form and green in color turquoise distinguished by its color and harder than chrysocolla
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