Download Descriptive Mineralogy Native Elements:

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Classification of the Minerals
Descriptive Mineralogy
Native Elements:
Pure elements that occur
as minerals
Native Elements
• Non-Silicates
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–
–
–
–
–
–
–
Native Elements
Halides
Sulfides
Oxides
Hydroxides
Carbonates
Sulfates
Phosphates
• Silicates
–
–
–
–
–
–
Orthosilicates
Sorosilicates
Cyclosilicates
Chain Silicates
Layer Silicates
Tektosilicates
Native Elements: Metals
• Fe, Co, Ni: Meteorites
• Platinum Group: (Ru, Rh, Pd, Os, Ir, Pt):
Mafic Igneous Rocks
• Coinage metals: Cu, Ag, Au
– Cu, Ag: Supergene Enrichments (Sulfide
Oxidation)
– Au: Low Temperature Hydrothermal, Placer
Native Iron: Meteorites
Native Iron: Meteorites
Widmanstätten Pattern
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Iron-Nickel Phase Diagram
FCC
B
C
C
Bushvelt: Layered Gabbroic Intrusion
Platinum Group Metals
Ru, Rh, Pd, Os, Ir, Pt
• Strongly siderophile elements
• Enriched in Fe meteorites
• Found in layered mafic intrusions
– Bushvelt Complex (South Africa)
– Stillwater Complex (Montana)
– Skaergaard Complex (Greenland)
Bushvelt: Layered Gabbroic Intrusion
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Skaergaard: Layered Gabbroic Intrusion
Skaergaard: Layered Gabbroic Intrusion
Skaergaard: Layered Gabbroic Intrusion
Native Elements: Cu, Ag, Au
• Cu and Ag: Supergene Enrichment
– Oxidation of Cu, Ag sulfides in
unsaturated zone
– Precipitation of metal, oxides and
carbonates at water table
• Ag and Au: hydrothermal
– Native metals and tellurides
• Au: placer
– oxidized hydrothermal
Supergene Copper
Hydrothermal Silver
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Hydrothermal Gold
Hydrothermal Gold
Gold Tellurides
Native Elements: non metals
• Calaverite (AuTe2)
• Krennerite (Au3AgTe8)
• Sylvanite (AuAgTe4)
• All weather to TeO2 + native gold
• Carbon:
– Graphite: Metamorphic Rocks
– Diamond: Kimberlites
• Sulfur (+Se):
– Salt Domes (Sulfate reduction),
– Volcanos (H2S oxidation)
• Tellurium (Te) Telluride
oxidation
Native Elements: Carbon
• Graphite (Low Pressure)
– Metamorphosed Organic-rich sediments
• Diamond (High Pressure >100km)
– Kimberlites
– Placers from kimberlites
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Native Elements: Diamond
Native Elements: Diamond
Kimberley Mine 1875
Native Elements: Sulfur
Fumarole Sulfur: Nysseros
• Fumaroles (Volcanic hydrothermal vents)
– Oxidation of H2S
• Salt dome cap rocks
– Sulfate reduction by petroleum
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Fumarole Sulfur: Kilauea
In the caps of salt domes, gypsum
(CaSO4 2H2O) is reduced to native sulfur
Native Elements
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