Weissbergite is an extremely rare thallium-antimony sulfide mineral typically found as delicate acicular crystals. It is primarily known from the historic Allchar mine in North Macedonia, where it occurs within epithermal sulfosalt deposits. Collectors should treat it with high care due to the toxic nature of thallium.
Is this weissbergite?
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 weissbergite with a known reference. Weissbergite sits at Mohs 1.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Weissbergite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Weissbergite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: acicular or fibrous crystals.
Often confused with
Weissbergite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Weissbergite leaves white, Stibnite leaves lead-gray; luster reads adamantine on Weissbergite and metallic on Stibnite.
How to tell apart: Streak differs — Weissbergite leaves white, Orpiment leaves yellow; luster reads adamantine on Weissbergite and resinous on Orpiment.
Often found alongside weissbergite
Minerals reported to co-occur with weissbergite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- TlSbS₂
- Mohs hardness
- 1.5
- Density
- 6.35 g/cm³
- Streak
- White
- Luster
- Adamantine
- Transparency
- Transparent
- Crystal system
- Tetragonal
- Crystal habit
- Acicular or Fibrous Crystals
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Epithermal Deposits
- Typical price
- $100-500 per specimen
Where rockhounds find weissbergite
Classic worldwide localities
- Allchar, North Macedonia
Field-hunting tip
Look in epithermal deposits country — that is the host setting where weissbergite typically forms. If you start seeing stibnite, orpiment, realgar in float, you are in the right ground. Field specimens usually show a acicular or fibrous crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find weissbergite on the map
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