NON-SILICATES

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NON-SILICATES
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Non Silicates

• Native Elements
• 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)
• sulfarsenidessemimetals 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
• chalcociteresembles enargite but has no cleavage
• bornitepeacock oredisplays 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 mineralthe 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 fools 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
• 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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• zincite
• red and occurs often with franklinite
• Hematite group
• isostructural group6 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
• 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
• isostructural groupfirst 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 formmost important
  ore of Al

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• Halides
• consists of minerals with a halogen anion
• examples are
• 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
• 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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• 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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• 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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• 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
• 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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• Hydrous Sulfate group
• examples are
• 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
• an example is
• wulfenite
• characterized by its orange-yellow color, high
  S.G. and tabular (tetragonal) crystals
• Vanadates
• an example is
• 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