Chromite is the primary ore of chromium and is typically found as black, opaque masses or octahedral crystals in ultramafic rocks. It is weakly magnetic and can be distinguished from magnetite by its characteristic dark brown streak and lack of strong magnetism. Collectors often look for well-defined octahedral crystals associated with green serpentine matrix.
Is this chromite?
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 chromite with a known reference. Chromite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic to submetallic.
- 4Match the color rangeCompare against the expected color range: black, brownish-black.
- 5Look at form & habitCrystal system: cubic. Typical habit: granular, massive, nuggets.
Often confused with
Chromite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Chromite leaves brown, Magnetite leaves black.
How to tell apart: Streak differs, so Chromite leaves brown, Ilmenite leaves black to reddish brown.
How to tell apart: Streak differs, so Chromite leaves brown, Franklinite leaves reddish brown to black.
Often found alongside chromite
Minerals reported to co-occur with chromite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeCr₂O₄
- Mohs hardness
- 5.5
- Density
- 4.5-5.09 g/cm³
- Colors
- Streak
- Brown
- Luster
- Metallic to submetallic
- Transparency
- Translucent to opaque
- Crystal system
- Cubic
- Crystal habit
- Granular, massive, nuggets
- Cleavage
- Parting may develop along {111}
- Rarity
- Common
- Uses
- Industrial, Collector
- Host rock
- A cumulus mineral in ultramafic portions of layered mafic igneous rocks; an accessory mineral in alpine-type peridotites; also detrital
Where rockhounds find chromite
17 mapped spotsClassic worldwide localities
- Stillwater complex, Montana, USA
- Gassin, Var, France
- Hangha, Sierra Leone
- Tiebaghi, New Caledonia
- Economic deposits in: the Bushveld complex, Transvaal, South Africa
- Great Dyke, Zimbabwe
Field-hunting tip
Where it forms: A cumulus mineral in ultramafic portions of layered mafic igneous rocks; an accessory mineral in alpine-type peridotites; also detrital. If you start seeing olivine, enstatite, plagioclase in float, you are in the right ground. Typical habit: granular, massive, nuggets. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in California, Maryland, North Carolina. Start trip planning there.
More chromite photos
Common questions
How do you identify chromite?+
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Find chromite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
