Marrite is a rare lead-silver-arsenic sulfosalt mineral primarily known from the famous Lengenbach Quarry in Switzerland. It typically occurs as small, dark, metallic tabular crystals embedded in dolomite and is highly prized by systematic mineral collectors.
Is this marrite?
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 marrite with a known reference. Marrite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray, steel gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: striated, tabular.
Often confused with
Marrite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Marrite leaves brownish black, Sartorite leaves chocolate-brown.
How to tell apart: Streak differs, so Marrite leaves brownish black, Baumhauerite leaves chocolate-brown.
How to tell apart: Marrite is noticeably harder (Mohs 3 vs. 1.5-2); streak differs, so Marrite leaves brownish black, Hutchinsonite leaves red; luster reads metallic on Marrite and adamantine to submetallic on Hutchinsonite.
Often found alongside marrite
Minerals reported to co-occur with marrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbAgAsS₃
- Mohs hardness
- 3
- Density
- 6.23 g/cm³
- Colors
- Streak
- Brownish black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Striated, tabular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Of hydrothermal origin, in dolostone
Where rockhounds find marrite
Classic worldwide localities
- Lengenbach quarry, Binntal, Valais, Switzerland (type locality)
Field-hunting tip
Where it forms: Of hydrothermal origin, in dolostone. If you start seeing lengenbachite, rathite, tennantite in float, you are in the right ground. Typical habit: striated, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify marrite?+
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Is marrite safe to handle?+
What rocks look like marrite?+
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Find marrite on the map
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