Sylvanite

Infobox mineral
name = Sylvanite
category = Telluride Mineral
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formula = (Ag,Au)Te₂
molweight = 429.89 gm
color = Silver-grey, Silver-white
habit = Massive to Crystaline
system = Monoclinic - Prismatic
twinning =
cleavage = Perfect on the {010}
fracture = Uneven
tenacity = Brittle
mohs = 1.5-2
luster = Metallic
polish =
refractive =
opticalprop = Anisotropic
birefringence =
dispersion =
pleochroism = None
fluorescence= None
absorption =
streak = steel grey
gravity = 8.2
density = 8.1
melt =
fusibility =
diagnostic =
solubility =
diaphaneity = opaque
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references = [ [http://www.mindat.org/min-3849.html Sylvanite: Sylvanite mineral information and data ] ] [ [http://webmineral.com/data/Sylvanite.shtml Sylvanite Mineral Data ] ] [ [http://mineral.galleries.com/minerals/sulfides/sylvanit/sylvanit.htm SYLVANITE (Silver Gold Telluride) ] ]

Sylvanite or silver gold telluride, (Ag,Au)Te₂, is the most common telluride of gold. The gold:silver ratio varies from 3:1 to 1:1. It is a metallic mineral with a color that ranges from a steely gray to almost white. It is closely related to calaverite. Sylvanite crystallizes in the monoclinic 2/m system. Crystals are rare and it is usually bladed or granular. It is very soft with a hardness of 1.5 - 2. It has a high relative density of 8 - 8.2. Sylvanite is photosensitive and can accumulate a dark tarnish if it is exposed to bright light for too long. Sylvanite represent a minor ore of gold and tellurium.

Occurrence

Sylvanite is found in Transylvania from which its name is derived. It is also found and mined in Australia in the East Kalgoorlie district. In Canada it is found in the Kirkland Lake Gold District, Ontario and the Rouyn District, Quebec. In the United States it occurs in California and in Colorado where it was mined as part of the Cripple Creek ore deposit. Sylvanite is associated with native gold, quartz, fluorite, rhodochrosite, pyrite, acanthite, nagyagite, calaverite, krennerite, and other rare telluride minerals. It is found most commonly in low temperature hydrothermal vein deposits.

References and external links

*Hurlbut, Cornelius S.; Klein, Cornelis, 1985, "Manual of Mineralogy", 20th ed., ISBN 0-471-80580-7