Trevorite is a rare nickel-iron member of the spinel group, frequently identified by its distinct metallic luster and strong magnetism. It is typically found as small, black, octahedral crystals associated with ultramafic deposits or contact metasomatic zones. Collectors prize it for its unique chemical composition and locality-specific occurrences in nickel mining districts.
Is this trevorite?
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 trevorite with a known reference. Trevorite sits at Mohs 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.
- 4Match the color rangeCompare against the expected color range: black.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals, massive.
Often confused with
Trevorite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Trevorite leaves brown, Magnetite leaves black.
How to tell apart: Franklinite is the harder of the two (Mohs ~6 vs. 5); streak differs, so Trevorite leaves brown, Franklinite leaves reddish brown to black.
Often found alongside trevorite
Minerals reported to co-occur with trevorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NiFe³⁺₂O₄
- Mohs hardness
- 5
- Density
- 5.164 g/cm³
- Colors
- Streak
- Brown
- Luster
- Metallic
- Transparency
- Opaque, transparent in thinnest fragments
- Crystal system
- Cubic
- Crystal habit
- Octahedral crystals, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In a small tabular body of nickeliferous serpentinite, probably a contact deposit, along the junction of quartzite and an ultramafic intrusive (Bon Accord, South Africa)
Where rockhounds find trevorite
Classic worldwide localities
- Found three km west of the Scotia talc mine, Bon Accord area, Barberton, Transvaal, South Africa
- Mt. Clifford nickel deposit, 54 km north-northwest of Leonora, Western Australia
Field-hunting tip
Where it forms: In a small tabular body of nickeliferous serpentinite, probably a contact deposit, along the junction of quartzite and an ultramafic intrusive (Bon Accord, South Africa). If you start seeing nimite, willemseite, nickeloan talc in float, you are in the right ground. Typical habit: octahedral crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find trevorite on the map
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