| Sylvanite | |
|---|---|
2Te4)%2c_Cripple_Creek_Diatreme.jpg) Sylvanite from theCripple Creek mining district | |
| General | |
| Category | Telluride mineral |
| Formula | (Ag,Au)Te2 |
| IMA symbol | Syv[1] |
| Strunz classification | 2.EA.05 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (sameH-M symbol) |
| Space group | P2/c |
| Identification | |
| Formula mass | 429.89 g/mol |
| Color | Silver-grey, silver-white |
| Crystal habit | Massive tocrystalline |
| Cleavage | Perfect on the {010} |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 1.5–2 |
| Luster | Metallic |
| Streak | Steel grey |
| Diaphaneity | Opaque |
| Specific gravity | 8.2 |
| Density | 8.1 |
| Optical properties | Anisotropic |
| Pleochroism | None |
| Ultravioletfluorescence | None |
| References | [2][3][4] |
Sylvanite orsilver gold telluride, chemical formula(Ag,Au)Te2, is the most commontelluride ofgold.
The gold:silver ratio varies from 3:1 to 1:1. It is ametallicmineral with a color that ranges from a steely gray to almost white. It is closely related tocalaverite, which is more purely gold telluride with 3% silver. Sylvanite crystallizes in themonoclinic 2/m system. Crystals are rare and it is usually bladed or granular. It is very soft with ahardness of 1.5–2. It has a high relativedensity of 8–8.2. Sylvanite isphotosensitive and can accumulate a darktarnish if it is exposed to brightlight for too long.
Sylvanite is found inTransylvania, from which its name is partially derived.[5] It is also found and mined inAustralia in the EastKalgoorlie district. InCanada it is found in the Kirkland Lake Gold District,Ontario and the Rouyn District,Quebec. In theUnited States it occurs inCalifornia and inColorado where it was mined as part of theCripple Creekore 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 temperaturehydrothermal vein deposits.
Sylvanite represents a minor ore of gold and tellurium.Sylvanium, an obsolete term for tellurium, derived its name from sylvanite.[6]
Chisholm, Hugh, ed. (1911)."Sylvanite" .Encyclopædia Britannica (11th ed.). Cambridge University Press.