Sinnerite is an extremely rare copper arsenic sulfide primarily known from the famous Lengenbach locality in the Binntal, Switzerland. It usually appears as small, metallic grey to black grains embedded within dolomitic marble and is primarily of interest to systematic mineral collectors.
Is this sinnerite?
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 sinnerite with a known reference. Sinnerite sits at Mohs ~4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: gray-black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: steel gray.
- 5Look at form & habitCrystal system: triclinic. Typical habit: columnar, twinning common.
Often confused with
Sinnerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Sinnerite leaves gray-black, Tennantite leaves reddish gray.
How to tell apart: Sinnerite is noticeably harder (Mohs ~4 vs. 3); streak differs, so Sinnerite leaves gray-black, Enargite leaves grayish black.
Often found alongside sinnerite
Minerals reported to co-occur with sinnerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₆As₄S₉
- Mohs hardness
- ~4
- Density
- 5.2 g/cm³
- Colors
- Streak
- Gray-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Columnar, twinning common
- Cleavage
- Indistinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- On sulfides in crystalline dolostone
Where rockhounds find sinnerite
Classic worldwide localities
- Lengenbach quarry, Binntal, Valais, Switzerland (type locality)
Field-hunting tip
Where it forms: On sulfides in crystalline dolostone. If you start seeing realgar, coloradoite, tennantite in float, you are in the right ground. Typical habit: columnar, twinning common. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify sinnerite?+
Where is sinnerite found?+
Is sinnerite safe to handle?+
What rocks look like sinnerite?+
What minerals are found with sinnerite?+
What kind of rock does sinnerite form in?+
What is sinnerite used for?+
Find sinnerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
