Protochabournéite is an exceptionally rare sulfosalt mineral containing both thallium and arsenic. It is primarily found in hydrothermal deposits, often occurring as microscopic aggregates associated with other rare thallium minerals.
Is this protochabournéite?
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 protochabournéite with a known reference. Protochabournéite 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. Protochabournéite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Protochabournéite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: black, lead-gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral grains, tabular aggregates.
Often confused with
Protochabournéite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Protochabournéite leaves black, Realgar leaves orange-red; luster reads metallic on Protochabournéite and resinous on Realgar.
How to tell apart: Streak differs — Protochabournéite leaves black, Orpiment leaves yellow; luster reads metallic on Protochabournéite and resinous on Orpiment.
Often found alongside protochabournéite
Minerals reported to co-occur with protochabournéite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₅(Sb,As)₉S₁₇
- Mohs hardness
- 2.5
- Density
- 4.9 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral Grains, Tabular Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Mineral Deposits
- Typical price
- $50-300+ depending on matrix size and locality rarity
Where rockhounds find protochabournéite
Classic worldwide localities
- Jas Roux, Hautes-Alpes, France
- Allchar, North Macedonia
Field-hunting tip
Look in hydrothermal mineral deposits country — that is the host setting where protochabournéite typically forms. If you start seeing chabournéite, realgar, orpiment in float, you are in the right ground. Field specimens usually show a anhedral grains, tabular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find protochabournéite on the map
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