Clino-oscarkempffite is an exceptionally rare sulfosalt mineral primarily identified from the San Jose mine in Bolivia. It typically appears as fine, metallic, lead-gray acicular crystals that require microscopic examination or X-ray diffraction to distinguish from related bismuth-sulfosalts.
Is this clino-oscarkempffite?
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 clino-oscarkempffite with a known reference. Clino-oscarkempffite 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. Clino-oscarkempffite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Clino-oscarkempffite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, steel-gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular to prismatic crystals.
Often confused with
Clino-oscarkempffite vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Clino-oscarkempffite is noticeably harder (Mohs 3.5 vs. 2.5).

How to tell apart: Clino-oscarkempffite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs — Clino-oscarkempffite leaves black, Galena leaves lead-gray.

How to tell apart: Clino-oscarkempffite is noticeably harder (Mohs 3.5 vs. 2); streak differs — Clino-oscarkempffite leaves black, Bismuthinite leaves lead-gray.
Often found alongside clino-oscarkempffite
Minerals reported to co-occur with clino-oscarkempffite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₁₆Pb₃₀Bi₃₈S₈₈
- Mohs hardness
- 3.5
- Density
- 6.68 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular to Prismatic Crystals
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Hydrothermal Veins
- Typical price
- $50-500 depending on specimen size and quality
Where rockhounds find clino-oscarkempffite
Classic worldwide localities
- San Jose mine, Oruro, Bolivia
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where clino-oscarkempffite typically forms. If you start seeing galena, bismuthinite, pyrite in float, you are in the right ground. Field specimens usually show a acicular to prismatic crystals habit, so train your eye for that shape before scanning the outcrop.


