Tetrahedrite
Tetrahedrite group
Common · Cu₆(Cu₄X₂)Sb₄S₁₃ (X = Fe, Zn, …)
Fahlore, from the German for pale: the grey copper ore of the old miners, one of the commonest sulfosalts, named in 1845 for its tetrahedral crystals. Since the 2020 nomenclature tetrahedrite is a series name for the species tetrahedrite-(Fe), tetrahedrite-(Zn) and their rarer kin. Historically an important copper ore, and worked for silver too, of which it can hold as much as 30 per cent; a minor copper ore today.
Identity
- Formula
- Cu₆(Cu₄X₂)Sb₄S₁₃ (X = Fe, Zn, …)
- Chemical class
- Sulfide
- Members
- Tetrahedrite-(Fe), Tetrahedrite-(Zn)
- Also known as
- Fahlore, Fahlerz, Grey copper ore
- Ore of
- Copper, Silver
Crystallography
- Crystal system
- Cubic
- Habits
- Pyramidal, Massive, Granular
- Fracture
- Subconchoidal
Physical properties
- Mohs hardness
- 3.5
- Density
- 4.97 g/cm³
- Luster
- Metallic
- Colors
- steel gray, iron-black, black
- Streak
- black to brown
- Transparency
- Opaque
Geology
- Origins
- Hydrothermal, Metamorphic
- Host rocks
- Granite, Marble
- Associated minerals
- Chalcopyrite, Galena, Sphalerite, Pyrite, Bornite, Acanthite, Siderite, Barite, Quartz
- Found in
- Hydrothermal vein (lode), Porphyry copper deposit, Skarn
- Geography
- Germany (Freiberg, Saxony; Clausthal, Harz), Austria (Brixlegg, Tyrol), Romania (Cavnic), Bolivia (Oruro), Peru (Casapalca, Quiruvilca), Mexico (Zacatecas)
Classification
- Rarity
- Common
- 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.
- C. Biagioni, L. L. George, N. J. Cook, E. Makovicky, Y. Moëlo, M. Pasero, J. Sejkora, C. J. Stanley, M. D. Welch, F. Bosi, The tetrahedrite group: Nomenclature and classification. American Mineralogist 105, 109–122, 2020.
- J. W. Anthony, R. A. Bideaux, K. W. Bladh, M. C. Nichols, Tetrahedrite. Mineral Data Publishing, Handbook of Mineralogy, 2001.
- Tetrahedrite. Wikipedia.
- Fahlore. Wikipedia.
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