Willemseite is a nickel-rich member of the serpentine group often mistaken for fine-grained chrysoprase or talc. It typically occurs as dense, massive, apple-green platy aggregates associated with nickel-laterite deposits.
Is this willemseite?
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 willemseite with a known reference. Willemseite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Willemseite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Willemseite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: apple-green, light green, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy, massive, fine-grained aggregates.
Often confused with
Willemseite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside willemseite
Minerals reported to co-occur with willemseite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ni,Mg)₃Si₄O₁₀(OH)₂
- Mohs hardness
- 2-3
- Density
- 2.8-3.0 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy, Massive, Fine-grained Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Scientific Reference
- Host rock
- Ultramafic Rocks and Weathering Zones of Nickel Ores
- Typical price
- $20-150 per specimen
Where rockhounds find willemseite
Classic worldwide localities
- Kraubath (Austria)
- Kambalda (Australia)
- Cerro Matoso (Colombia)
- Akhaltsikhe (Georgia)
Field-hunting tip
Look in ultramafic rocks and weathering zones of nickel ores country — that is the host setting where willemseite typically forms. If you start seeing magnesite, quartz, nickel-bearing silicates in float, you are in the right ground. Field specimens usually show a platy, massive, fine-grained aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify willemseite?+
Where is willemseite found?+
How much is willemseite worth?+
What rocks look like willemseite?+
What minerals are found with willemseite?+
What kind of rock does willemseite form in?+
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Find willemseite on the map
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