Famatinite is a rare copper antimony sulfide often found as a massive or granular mineral in hydrothermal deposits. It is easily confused with its dimorph enargite, typically distinguished by a slightly redder metallic luster and distinct copper-deep pinkish brown tint in reflected light.
Is this famatinite?
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 famatinite with a known reference. Famatinite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: dull metallic.
- 4Match the color rangeCompare against the expected color range: grayish black, dark pink brown, steel gray.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: massive, granular, or crusts.
Often confused with
Famatinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Famatinite leaves black, Enargite leaves grayish black; luster reads dull metallic on Famatinite and metallic to dull on Enargite.
How to tell apart: Luster reads dull metallic on Famatinite and metallic, commonly splendent on Tetrahedrite.
How to tell apart: Streak differs, so Famatinite leaves black, Stannite leaves blackish; luster reads dull metallic on Famatinite and metallic on Stannite.
Often found alongside famatinite
Minerals reported to co-occur with famatinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃SbS₄
- Mohs hardness
- 3.5
- Density
- 4.635 g/cm³
- Colors
- Streak
- Black
- Luster
- Dull metallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Massive, granular, or crusts
- Cleavage
- {101}, good; {100}, distinct
- Rarity
- Uncommon
- Uses
- Collector, Ore of copper
- Host rock
- In copper deposits formed at low to medium temperatures
Where rockhounds find famatinite
Classic worldwide localities
- Goldfield, Esmeralda Co., Nevada, USA
- Tombstone and the Campbell mine, Bisbee, Cochise Co., Arizona, USA
- Magma mine, Superior, Pinal Co., Arizona, USA
- Butte, Silver Bow Co., Montana, USA
- Sierra de Famatina, La Rioja Province, Argentina (type locality)
- Cananea, Sonora, Mexico
Field-hunting tip
Where it forms: In copper deposits formed at low to medium temperatures. If you start seeing pyrite, enargite, tetrahedrite–tennantite in float, you are in the right ground. Typical habit: massive, granular, or crusts. Train your eye for that shape before scanning the outcrop.
Common questions
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Find famatinite on the map
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