Formula: AgAuTe4
Crystal System: Monoclinic
Specific gravity: 8.16 measured, 8.161 calculated
Hardness: 1½ to 2
Streak: Grey
Colour: Silver-grey, whitish
Solubility: Insoluble in water, hydrochloric and sulphuric acid; slightly soluble in nitric acid
Common impurities: Sb,Pb,Cu,Ni

Hydrothermal environments

Sylvanite occurs most commonly in low-temperature hydrothermal veins, but also in moderate and high temperature deposits; it is usually among the last minerals formed (Webmin). Associated minerals include gold, calaverite, krennerite, altaite, hessite, petzite, acanthite, pyrite, galena, sphalerite, chalcopyrite, quartz, chalcedony and fluorite (HOM).


At Cobar, New South Wales, Australia, sylvanite is a minor ore mineral (AJM 11.2.69)

At the Kalgoorlie district, Western Australia, good specimens of sylvanite with gold have been found. Associated minerals include calaverite, hessite, petzite, coloradoite, chalcopyrite, tetrahedrite, quartz, apatite and tourmaline (R&M 96.3.206).

At the Ida May deposit, Bridge River area, Lillooet Mining Division, British Columbia, Canada, sylvanite occurs with native gold and stibnite (R&M 96.3.205).

In an occurrence at Fortune Lake, Arntfield, Rouyn-Noranda TE, Abitibi-Témiscamingue, Quebec, Canada, spectacular showings of sylvanite, gold and petzite were found in quartz-ankerite veins (R&M 96.3.205).

At the Buffalo Hump claims on Mount Stevens, Yukon Territory, Canada, sylvanite is found with galena and gold (R&M 96.3.205).

At Gold Hill, Wheaton River District, Whitehorse mining district, Yukon, Canada, sylvanite occurs with hessite, petzite and gold (R&M 96.3.206).

At the Emperor Mine, Vatukoula, Vatukoula Gold Field, Viti Levu, Fiji, fine sharply developed, deeply striated lustrous crystals of sylvanite to 3.5 cm long are associated with quartz, gold, petzite, coloradoite, krennerite, empressite, nagyágite, hessite, melonite, native tellurium, arsenopyrite and stibnite (R&M 96.3.206).

At the type locality, Baia de Arieș, Alba, Romania, sylvanite is associated with gold (R&M 96.3.206).

Sylvanite from Baia de Arieș - Image

At the Sugarman and Nigger Mine, Browns Flat, Columbia District, East Belt, Tuolumne county, California, USA, exceptional gold specimens with sylvanite and petzite have been found (R&M 96.3.205).

At Boulder county, Colorado, USA, sylvanite occurs with native gold in many localities (R&M 96.3.205).

At Cripple Creek, Teller county, Colorado, USA, sylvanite is found associated with calaverite and krennerite, and sometimes pseudomorphed by gold (MinRec 36.2.179).

At the Cresson Mine, Eclipse Gulch, Cripple Creek Mining District, Teller county, Colorado, USA, in a vug 12 x 6 x 4 metres in size, discovered in 1914, well crystallised calaverite, sylvanite and flaky native gold associated with celestine were found (R&M 96.3.205).

At the Trojan District, Lawrence county, South Dakota, USA, fine sylvanite specimens have been found with minor gold (R&M 96.3.205).

At the Tintic Mining District, Utah, USA, sylvanite occurs mostly as solid metallic masses in gold ores from the eastern part of the district, although not in great abundance. It has been reported from the Trixie, Tintic Standard, Eureka Standard and North Star mines. A specimen with a vein of massive sylvanite in quartz associated with pyrite has been found (MinRec 55.2.223).

Sylvanite from Tintic - Image

At the Beecher Mine, Rockcut, Orient District, Stevens county, Washington, USA, sylvanite is intimately associated with gold (R&M 96.3.205).

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