Gabrielsonite is an extremely rare lead-iron arsenate mineral found almost exclusively in the famous Långban mines of Sweden. It typically appears as black, resinous to vitreous crusts or fine-grained aggregates associated with manganese and iron minerals. Due to its extreme rarity and high arsenic-lead content, it is primarily a target for specialized micromount or advanced mineral species collectors.
Is this gabrielsonite?
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 gabrielsonite with a known reference. Gabrielsonite 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. Streak: pale chocolate-brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine.
- 4Match the color rangeCompare against the expected color range: black, greenish brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: aggregates, nodular, spherical.
Often confused with
Gabrielsonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gabrielsonite leaves pale chocolate-brown, Mimetite leaves white; luster reads adamantine on Gabrielsonite and resinous to subadamantine on Mimetite.
How to tell apart: Adelite is the harder of the two (Mohs 5 vs. 3.5); streak differs, so Gabrielsonite leaves pale chocolate-brown, Adelite leaves white; luster reads adamantine on Gabrielsonite and resinous on Adelite.
Often found alongside gabrielsonite
Minerals reported to co-occur with gabrielsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbFe(AsO₃)O
- Mohs hardness
- 3.5
- Density
- 6.67 g/cm³
- Colors
- Streak
- Pale chocolate-brown
- Luster
- Adamantine
- Transparency
- Transparent in small fragments
- Crystal system
- Orthorhombic
- Crystal habit
- Aggregates, nodular, spherical
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a metamorphosed Fe–Mn orebody
Where rockhounds find gabrielsonite
Classic worldwide localities
- Långban, Värmland, Sweden
Field-hunting tip
Where it forms: In a metamorphosed Fe–Mn orebody. If you start seeing roméite, nadorite, finnemanite in float, you are in the right ground. Typical habit: aggregates, nodular, spherical. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gabrielsonite?+
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What rocks look like gabrielsonite?+
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Find gabrielsonite on the map
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