Linnaeite is a rare cobalt sulfide mineral that typically appears as metallic, steel-gray octahedrons. It is primarily found in hydrothermal veins associated with other sulfide minerals and is a historically significant minor ore of cobalt.
Is this linnaeite?
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 linnaeite with a known reference. Linnaeite sits at Mohs 4.5-5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Linnaeite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Linnaeite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: steel-gray, pale pinkish-gray, silver-white.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals, massive, granular.
Often confused with
Linnaeite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Linnaeite leaves black, Pentlandite leaves light bronze-brown.
How to tell apart: Streak differs — Linnaeite leaves black, Cobaltite leaves greyish-black.
How to tell apart: Streak differs — Linnaeite leaves black, Pyrite leaves greenish-black to brownish-black.
Often found alongside linnaeite
Minerals reported to co-occur with linnaeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Co₃S₄
- Mohs hardness
- 4.5-5.5
- Density
- 4.8-5.0 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Cubic
- Crystal habit
- Octahedral Crystals, Massive, Granular
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Ore of Cobalt
- Host rock
- Hydrothermal Veins, Contact Metamorphic Deposits
- Typical price
- $20-150 for specimens depending on size and quality
Where rockhounds find linnaeite
1 mapped spotsClassic worldwide localities
- Bastnäs Mines, Sweden
- Siegen, Germany
- Katanga, DR Congo
- Fredericktown, Missouri, USA
- Sudbury, Ontario, Canada
Field-hunting tip
Look in hydrothermal veins, contact metamorphic deposits country — that is the host setting where linnaeite typically forms. If you start seeing chalcopyrite, galena, sphalerite in float, you are in the right ground. Field specimens usually show a octahedral crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wyoming — start trip planning there.
Common questions
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Find linnaeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
