Pierrotite is a very rare thallium-arsenic sulfosalt primarily known from the unique Allchar deposit in North Macedonia. It typically appears as lead-gray acicular crystals that can be difficult to distinguish from other sulfosalts without advanced analytical techniques.
Is this pierrotite?
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 pierrotite with a known reference. Pierrotite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pierrotite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Pierrotite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular crystals, striations on crystal faces.
Often confused with
Pierrotite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Pierrotite leaves black, Stibnite leaves lead-gray.
How to tell apart: Streak differs, so Pierrotite leaves black, Realgar leaves orange-red; luster reads metallic on Pierrotite and resinous on Realgar.
How to tell apart: Streak differs, so Pierrotite leaves black, Lorandite leaves cherry-red.
Often found alongside pierrotite
Minerals reported to co-occur with pierrotite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₂Sb₁₀As₄S₁₈
- Mohs hardness
- 2.5
- Density
- 4.8 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular Crystals, Striations On Crystal Faces
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mineral Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find pierrotite
Classic worldwide localities
- Allchar, North Macedonia
Field-hunting tip
Look in hydrothermal mineral deposits country, the host setting where pierrotite typically forms. If you start seeing lorandite, stibnite, realgar in float, you are in the right ground. Field specimens usually show a acicular crystals, striations on crystal faces habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify pierrotite?+
Where is pierrotite found?+
How much is pierrotite worth?+
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Find pierrotite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
