Copper arsenic sulfide of the tetrahedrite group. Forms a solid solution series with tetrahedrite. Color: Steel-gray to iron-black. Luster: Metallic to submetallic. Streak: Dark red to brown. Cleavage: None. Hardness: 3-4.5. Transparency: Opaque. Crystal system: Isometric Cubic. Chemical formula: Cu₁₂As₄S₁₃. Specific gravity: 4.6-4.7. Formation: Forms in hydrothermal copper-zinc-lead veins at moderate temperatures. Common geological settings: England, Germany, Peru, Mexico; found in polymetallic veins. Common look-alikes and related entries: Tetrahedrite, Sphalerite, Chalcopyrite. Specimen safety: Keep this arsenic-bearing specimen intact. Do not cut, grind, polish, streak, lick, heat, or use acid on it. Avoid creating or breathing dust or fumes, wash your hands with soap and water after handling, and keep it away from food, children, and pets.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
Editorial owner
GeoMiner
Last updated
2026-03-30T14:37:52.575271+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Arsenic (inorganic compounds, as As) — CDC/NIOSH. Official occupational-hazard, exposure-route, symptom, and protective-equipment information for inorganic arsenic compounds.
Copper arsenic sulfide of the tetrahedrite group. Forms a solid solution series with tetrahedrite.
How can you identify Tennantite?
Compare several properties rather than relying on colour alone. This entry records colour: Steel-gray to iron-black; lustre: Metallic to submetallic; streak: Dark red to brown; Mohs hardness: 3-4.5; cleavage: None; crystal system: Isometric Cubic; transparency: Opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Tennantite form?
Forms in hydrothermal copper-zinc-lead veins at moderate temperatures.
Where is Tennantite commonly found?
England, Germany, Peru, Mexico; found in polymetallic veins.
Is Tennantite safe to handle?
Keep this arsenic-bearing specimen intact. Do not cut, grind, polish, streak, lick, heat, or use acid on it. Avoid creating or breathing dust or fumes, wash your hands with soap and water after handling, and keep it away from food, children, and pets. Avoid creating dust or using destructive tests on an unknown specimen, and follow site-specific safety procedures.
What is Tennantite commonly confused with?
Tennantite may be confused with Tetrahedrite, Sphalerite, Chalcopyrite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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