Kullerudite is a rare nickel selenide mineral that typically occurs in low-temperature hydrothermal veins. It is visually similar to other metallic sulfide minerals and is primarily sought after by advanced collectors of rare-element species.
Is this kullerudite?
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 kullerudite with a known reference. Kullerudite sits at Mohs 5.5-6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: lead gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive.
Often confused with
Kullerudite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Kullerudite leaves black, Marcasite leaves grayish or brownish black.
How to tell apart: Streak differs, so Kullerudite leaves black, Pyrite leaves greenish black to brownish black.
Often found alongside kullerudite
Minerals reported to co-occur with kullerudite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NiSe₂
- Mohs hardness
- 5.5-6.5
- Density
- 6.72 g/cm³
- Colors
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Reference mineral
- Host rock
- In calcite veins in sills of albite diabase in schist, associated with low-grade uranium mineralization, almost exclusively as an alteration product of wilkmanite
Where rockhounds find kullerudite
Classic worldwide localities
- Kuusamo, northeastern Finland (type locality)
Field-hunting tip
Where it forms: In calcite veins in sills of albite diabase in schist, associated with low-grade uranium mineralization, almost exclusively as an alteration product of wilkmanite. If you start seeing wilkmanite, sederholmite, penroseite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kullerudite?+
Where is kullerudite found?+
Is kullerudite safe to handle?+
What rocks look like kullerudite?+
What minerals are found with kullerudite?+
What kind of rock does kullerudite form in?+
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Find kullerudite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
