Tetrahedrite is the most common member of the fahlore group, known for its distinctive sharp tetrahedral crystal form. It is a major ore for copper and silver and is frequently found in hydrothermal vein deposits alongside various other sulfides. Its metallic luster and dark color often make it a striking addition to mineral collections when found as well-defined, lustrous crystals.
Is this tetrahedrite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch tetrahedrite with a known reference. Tetrahedrite sits at Mohs 3-4.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black to brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic, commonly splendent.
- 4Match the color rangeCompare against the expected color range: steel-gray, iron-black, black, iron gray, steel gray.
- 5Look at form & habitCrystal system: cubic. Typical habit: massive.
Often confused with
Tetrahedrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tetrahedrite leaves black to brown, Tennantite leaves reddish gray.
How to tell apart: Streak differs, so Tetrahedrite leaves black to brown, Galena leaves lead-gray.
How to tell apart: Streak differs, so Tetrahedrite leaves black to brown, Bournonite leaves steel-gray to iron-black; luster reads metallic, commonly splendent on Tetrahedrite and brilliant to dull on Bournonite.
Often found alongside tetrahedrite
Minerals reported to co-occur with tetrahedrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Fe,Zn,Ag)₁₂Sb₄S₁₃
- Mohs hardness
- 3-4.5
- Density
- 4.97 g/cm³
- Colors
- Streak
- Black to brown
- Luster
- Metallic, commonly splendent
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Common
- Uses
- Ore of copper, Ore of silver, Collector
- Host rock
- Typically in hydrothermal veins or contact metamorphic deposits of low to medium temperature of formation
Where rockhounds find tetrahedrite
9 mapped spotsClassic worldwide localities
- Daly-Judge and other mines, Park City district, Summit Co., Utah, USA
- Freiberg, Saxony, and in the Harz Mountains, at Clausthal and Horhausen, Germany
- Brixlegg, Tirol, Austria
- Botés, near Zlatna, and Cavnic (Kapnikbánya), Romania
- Irazein, Ariège, France, a few exceptionally large crystals, and from Sainte-Marie-aux-Mines, Haut-Rhin, France
- Cornwall, England, at the Herodsfoot mine
Field-hunting tip
Where it forms: Typically in hydrothermal veins or contact metamorphic deposits of low to medium temperature of formation. If you start seeing chalcopyrite, galena, sphalerite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, Idaho, Arizona. Start trip planning there.
Common questions
How do you identify tetrahedrite?+
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Find tetrahedrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
