Sylvanite
Species
Rare · AgAuTe₄
A gold and silver telluride, steel grey to silver white, whose twinned crystals can look like cuneiform writing. First found in Transylvania, at Săcărâmb and Baia de Arieș, and named for it and for "sylvanium", an early name for tellurium. Present in minor amounts in many gold and silver deposits but only rarely of economic importance, as at Cripple Creek, Colorado, and Kalgoorlie.
Identity
- Formula
- AgAuTe₄
- Chemical class
- Sulfide
- Also known as
- Graphic tellurium, Silver gold telluride
- Ore of
- Gold
Crystallography
- Crystal system
- Monoclinic
- Habits
- Prismatic, Tabular, Bladed, Granular
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 1.5
- Density
- 8.16 g/cm³
- Luster
- Metallic
- Colors
- steel gray, silver-white, pale yellow
- Streak
- steel gray to silver-white
- Transparency
- Opaque
Geology
- Origins
- Hydrothermal
- Host rocks
- Granite
- Associated minerals
- Gold, Calaverite, Acanthite, Pyrite, Galena, Sphalerite, Chalcopyrite, Quartz, Fluorite
- Found in
- Hydrothermal vein (lode)
- Geography
- Romania (Săcărâmb, Baia de Arieș), USA (Cripple Creek, Colorado), Australia (Kalgoorlie), Canada (Kirkland Lake, Ontario), Fiji (Emperor mine, Vatukoula)
Classification
- Rarity
- Rare
- Gem quality
- No
Sources
- M. Pasero and others, IMA Commission on New Minerals, Nomenclature and Classification, The New IMA List of Minerals, updated September 2026. International Mineralogical Association (CNMNC), 2026.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Sylvanite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Sylvanite. Wikipedia.
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