Skinnerite is a rare copper antimony sulfide mineral usually found in hydrothermal veins. It typically presents as small gray to black tabular crystals or in massive form, often appearing alongside other sulfide minerals like galena and sphalerite.
Is this skinnerite?
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 skinnerite with a known reference. Skinnerite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: reddish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: silver gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: irregular grains.
Often confused with
Skinnerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Skinnerite leaves reddish black, Tetrahedrite leaves black to brown.
How to tell apart: Streak differs, so Skinnerite leaves reddish black, Bournonite leaves steel-gray to iron-black; luster reads metallic on Skinnerite and brilliant to dull on Bournonite.
Often found alongside skinnerite
Minerals reported to co-occur with skinnerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₃SbS₃
- Mohs hardness
- 3.5-4
- Density
- 5.07 g/cm³
- Colors
- Streak
- Reddish black
- Luster
- Metallic
- Transparency
- Opaque, transparent in very thin sections
- Crystal system
- Monoclinic
- Crystal habit
- Irregular grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a complex of analcime-natrolite veins cutting naujaites (Ilímaussaq intrusion, Greenland)
Where rockhounds find skinnerite
Classic worldwide localities
- Belmont, Belmont district, Nye Co., Nevada, USA
- Ilímaussaq intrusion, southern Greenland (type locality)
- Clara mine, near Oberwolfach, Black Forest, Germany
- Košice, Czech Republic
Field-hunting tip
Where it forms: In a complex of analcime-natrolite veins cutting naujaites (Ilímaussaq intrusion, Greenland). If you start seeing sénarmontite, valentinite, tetrahedrite in float, you are in the right ground. Typical habit: irregular grains. Train your eye for that shape before scanning the outcrop.
Common questions
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Find skinnerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
