Cohenite is a rare iron carbide mineral found almost exclusively in iron meteorites. It typically appears as brittle, tin-white grains or thin plates within the nickel-iron matrix of metallic meteorites, serving as a key indicator of specific thermal conditions during the formation of planetary bodies.
Is this cohenite?
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 cohenite with a known reference. Cohenite sits at Mohs 5.5-6, 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: yellowish white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: granular, massive, plates.
Often confused with
Cohenite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Cohenite is noticeably harder (Mohs 5.5-6 vs. 4); streak differs, so Cohenite leaves gray-black, Kamacite leaves gray.
How to tell apart: Streak differs, so Cohenite leaves gray-black, Taenite leaves light gray.
How to tell apart: Streak differs, so Cohenite leaves gray-black, Schreibersite leaves dark gray; luster reads metallic on Cohenite and brilliant metallic on Schreibersite.
Often found alongside cohenite
Minerals reported to co-occur with cohenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe₃C
- Mohs hardness
- 5.5-6
- Density
- 7.20-7.65 g/cm³
- Colors
- Streak
- Gray-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Granular, massive, plates
- Cleavage
- {100}, {010}, and {001}
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In iron meteorites
Where rockhounds find cohenite
Classic worldwide localities
- Niaqornat (Niakornak) and on Disko Island, near Uivfaq and Kitdlı̂t, Greenland
- Bühl, near Weimar, Hesse, Germany
- Kopeysk, Chelyabinsk coal basin, Southern Ural Mountains, and in the Ijim massif, western Sayan Mountains, Tuva, Russia
- Burobaiskii massif, eastern Kazakhstan
Field-hunting tip
Where it forms: In iron meteorites. If you start seeing iron, schreibersite, troilite in float, you are in the right ground. Typical habit: granular, massive, plates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find cohenite on the map
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