Wilkmanite is a rare nickel selenide belonging to the pentlandite group, typically found as small grains or massive aggregates within hydrothermal deposits. It is recognized for its metallic white-to-gray luster and is most often associated with other rare selenium-bearing minerals in specialized geological settings.
Is this wilkmanite?
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 wilkmanite with a known reference. Wilkmanite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: grayish black.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: grayish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive.
Often confused with
Wilkmanite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Pentlandite is the harder of the two (Mohs 3.5-4 vs. 2.5); streak differs, so Wilkmanite leaves grayish black, Pentlandite leaves pale bronze-brown.
How to tell apart: Troilite is the harder of the two (Mohs 3.5-4.5 vs. 2.5); streak differs, so Wilkmanite leaves grayish black, Troilite leaves dark grayish brown.
Often found alongside wilkmanite
Minerals reported to co-occur with wilkmanite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₃Se₄
- Mohs hardness
- 2.5
- Density
- 6.96 g/cm³
- Colors
- Streak
- Grayish black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Massive
- Cleavage
- Good on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A primary phase and an alteration product of sederholmite, in albite diabase sills that cut a schist formation, associated with low-grade uranium mineralization
Where rockhounds find wilkmanite
Classic worldwide localities
- Kuusamo, northeastern Finland
Field-hunting tip
Where it forms: A primary phase and an alteration product of sederholmite, in albite diabase sills that cut a schist formation, associated with low-grade uranium mineralization. If you start seeing sederholmite, penroseite, selenium in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
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Find wilkmanite on the map
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