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, so Linnaeite leaves black, Pentlandite leaves light bronze-brown.
How to tell apart: Streak differs, so Linnaeite leaves black, Cobaltite leaves greyish-black.
How to tell apart: Streak differs, so 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, 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.
