Gabrielite is an extremely rare sulfosalt mineral found almost exclusively in the Binn Valley of Switzerland. It typically forms small, gray to black, tabular crystals embedded in dolomitic marble or associated with other rare arsenic-bearing sulfosalts.
Is this gabrielite?
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 gabrielite with a known reference. Gabrielite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Gabrielite leaves a blackish red streak.
- 3Read the lusterHold the specimen under a strong light. Gabrielite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: gray, black.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Gabrielite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Gabrielite leaves blackish red, Smithite leaves orange-red; luster reads metallic on Gabrielite and adamantine on Smithite.
How to tell apart: Streak differs, so Gabrielite leaves blackish red, Hutchinsonite leaves red; luster reads metallic on Gabrielite and adamantine on Hutchinsonite.
Often found alongside gabrielite
Minerals reported to co-occur with gabrielite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Tl₂AgCuAs₃S₆
- Mohs hardness
- 2
- Density
- 5.41 g/cm³
- Streak
- Blackish Red
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Dolomitic Limestone in Hydrothermal Deposits
Where rockhounds find gabrielite
Classic worldwide localities
- Lengenbach Quarry, Binn Valley, Switzerland
Field-hunting tip
Look in dolomitic limestone in hydrothermal deposits country, the host setting where gabrielite typically forms. If you start seeing realgar, orpiment, sartorite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find gabrielite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
