Uchucchacuaite is a rare lead-silver-antimony sulfosalt known primarily from its type locality in Peru. It typically appears as metallic, lead-grey tabular crystals or as massive, granular aggregates within hydrothermal silver deposits.
Is this uchucchacuaite?
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 uchucchacuaite with a known reference. Uchucchacuaite 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. Uchucchacuaite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Uchucchacuaite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: gray, lead-gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, massive, granular.
Often confused with
Uchucchacuaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Uchucchacuaite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Uchucchacuaite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs — Uchucchacuaite leaves black, Boulangerite leaves brownish-gray.
How to tell apart: Uchucchacuaite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Uchucchacuaite leaves black, Jamesonite leaves gray-black.
Often found alongside uchucchacuaite
Minerals reported to co-occur with uchucchacuaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AgPb₃Sb₅S₁₂
- Mohs hardness
- 3.5
- Density
- 6.08 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals, Massive, Granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find uchucchacuaite
Classic worldwide localities
- Uchucchacua Mine, Peru
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where uchucchacuaite typically forms. If you start seeing galena, pyrite, alabandite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify uchucchacuaite?+
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What rocks look like uchucchacuaite?+
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Find uchucchacuaite on the map
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