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, so Uchucchacuaite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs, so Uchucchacuaite leaves black, Boulangerite leaves brownish-gray.
How to tell apart: Uchucchacuaite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so 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, 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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Find uchucchacuaite on the map
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