Berthierite is a relatively uncommon iron antimony sulfide typically found in hydrothermal vein deposits. It is often confused with stibnite, but it lacks the characteristic highly flexible, sectile nature of stibnite and typically exhibits a more brittle, metallic character.
Is this berthierite?
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 berthierite with a known reference. Berthierite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Berthierite leaves a dark grey streak.
- 3Read the lusterHold the specimen under a strong light. Berthierite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: dark gray, iron black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic, fibrous, columnar, or massive.
Often confused with
Berthierite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Berthierite leaves dark grey, Stibnite leaves lead-gray.
How to tell apart: Streak differs — Berthierite leaves dark grey, Jamesonite leaves gray-black.
How to tell apart: Arsenopyrite is the harder of the two (Mohs 5.5-6 vs. 2-3); streak differs — Berthierite leaves dark grey, Arsenopyrite leaves black.
Often found alongside berthierite
Minerals reported to co-occur with berthierite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeSb₂S₄
- Mohs hardness
- 2-3
- Density
- 4.6-4.7 g/cm³
- Colors
- Streak
- Dark Grey
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic, Fibrous, Columnar, Or Massive
- Cleavage
- Poor
- Rarity
- Uncommon
- Uses
- Collector, Reference
- Host rock
- Low-to-medium Temperature Hydrothermal Veins
- Typical price
- $15-150 per specimen depending on size and crystal quality
Where rockhounds find berthierite
Classic worldwide localities
- Chazelles, France
- Herja, Romania
- Iskra, Bulgaria
- Wolfsberg, Germany
- Treptice, Czech Republic
Field-hunting tip
Look in low-to-medium temperature hydrothermal veins country — that is the host setting where berthierite typically forms. If you start seeing stibnite, pyrite, galena in float, you are in the right ground. Field specimens usually show a prismatic, fibrous, columnar, or massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find berthierite on the map
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