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Sylvanite



Sylvanite
CategoryTelluride Mineral
Chemical formula(Ag,Au)Te2
Identification
Molecular Weight429.89 gm
ColorSilver-grey, Silver-white
Crystal habitMassive to Crystaline
Crystal systemMonoclinic - Prismatic
CleavagePerfect on the {010}
FractureUneven
TenacityBrittle
Mohs Scale hardness1.5-2
LusterMetallic
Optical PropertiesAnisotropic
PleochroismNone
Ultraviolet fluorescenceNone
Streaksteel grey
Specific gravity8.2
Density8.1
Diaphaneityopaque
References[1] [2] [3]

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.

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

  1. ^ http://www.mindat.org/min-3849.html
  2. ^ http://webmineral.com/data/Sylvanite.shtml
  3. ^ http://mineral.galleries.com/minerals/sulfides/sylvanit/sylvanit.htm
  • Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., ISBN 0-471-80580-7
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Sylvanite". A list of authors is available in Wikipedia.
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