Twinnite is a rare lead-antimony sulfosalt mineral found primarily in metamorphic carbonate rocks. It is visually indistinguishable from other sulfosalts in the field and typically requires advanced analytical techniques like X-ray diffraction for positive identification.
Is this twinnite?
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 twinnite with a known reference. Twinnite 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. Twinnite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Twinnite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, massive, granular.
Often confused with
Twinnite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Twinnite leaves black, Sartorite leaves chocolate-brown.
How to tell apart: Streak differs, so Twinnite leaves black, Boulangerite leaves brownish-gray.
How to tell apart: Twinnite is noticeably harder (Mohs 3.5 vs. 2.5); streak differs, so Twinnite leaves black, Jamesonite leaves gray-black.
Often found alongside twinnite
Minerals reported to co-occur with twinnite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₁₄Sb₁₄S₃₃
- Mohs hardness
- 3.5
- Density
- 5.6-5.7 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Massive, Granular
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Dolomite Rocks
- Typical price
- $50-500 thumbnail, $200-2000 cabinet
Where rockhounds find twinnite
Classic worldwide localities
- Binntal, Switzerland
- Radusa, North Macedonia
- Boldut, Romania
Field-hunting tip
Look in dolomite rocks country, the host setting where twinnite typically forms. If you start seeing sartorite, baumhauerite, galena in float, you are in the right ground. Field specimens usually show a acicular crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find twinnite on the map
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