Debattistiite is a rare silver mercury arsenic sulfosalt that forms black tabular well-formed crystals. It is a rare hydrothermal mineral in dolomitic marble. Associated minerals include realgar, rutile and trechmannite. It was first described from Lengenbach quarry, Binn Valley, Valais, Switzerland.
Is this debattistiite?
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 debattistiite with a known reference. Debattistiite sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular well-formed crystals.
Often confused with
Debattistiite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Gudmundite is the harder of the two (Mohs ~5-6 vs. 2-2.5); streak differs, so Debattistiite leaves gray, Gudmundite leaves grayish black.
How to tell apart: Arsenopyrite is the harder of the two (Mohs 5.5-6 vs. 2-2.5); streak differs, so Debattistiite leaves gray, Arsenopyrite leaves black.
Often found alongside debattistiite
Minerals reported to co-occur with debattistiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ag₉Hg₀.₅As₆S₁₂Te₂
- Mohs hardness
- 2-2.5
- Density
- 5.647 g/cm³
- Colors
- Streak
- Gray
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Tabular well-formed crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare hydrothermal mineral in dolomitic marble
Where rockhounds find debattistiite
Classic worldwide localities
- Lengenbach quarry (zone 1), Binn Valley, Valais, Switzerland
Field-hunting tip
Where it forms: A rare hydrothermal mineral in dolomitic marble. If you start seeing realgar, rutile, trechmannite in float, you are in the right ground. Typical habit: tabular well-formed crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find debattistiite on the map
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