Nullaginite is a rare nickel carbonate that typically forms as bright green, delicate radiating sprays or crusts within weathering ultramafic deposits. It is most commonly found in association with other secondary nickel minerals in Australian localities and requires a hand lens to appreciate its fine acicular crystal structure.
Is this nullaginite?
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 nullaginite with a known reference. Nullaginite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: dull, claylike, silky in cross-vein fibers.
- 4Match the color rangeCompare against the expected color range: bright green, dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular, nodular.
Often confused with
Nullaginite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Zaratite is the harder of the two (Mohs 3.5 vs. 1.5-2); streak differs, so Nullaginite leaves pale green, Zaratite leaves light green; luster reads dull, claylike, silky in cross-vein fibers on Nullaginite and vitreous to greasy on Zaratite.
How to tell apart: Malachite is the harder of the two (Mohs 3.5-4 vs. 1.5-2); luster reads dull, claylike, silky in cross-vein fibers on Nullaginite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
Often found alongside nullaginite
Minerals reported to co-occur with nullaginite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₂(CO₃)(OH)₂
- Mohs hardness
- 1.5-2
- Density
- 3.56 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Dull, claylike, silky in cross-vein fibers
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Granular, nodular
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare mineral formed in the oxidation zone of nickel-rich hydrothermal ore deposits
Where rockhounds find nullaginite
Classic worldwide localities
- Otway nickel deposit, near Spinnaway, Nullagine district, and in the 132 North nickel mine, 4 km southwest of Widgiemooltha, Western Australia
Field-hunting tip
Where it forms: A rare mineral formed in the oxidation zone of nickel-rich hydrothermal ore deposits. If you start seeing magnesian pecoraite, gaspéite, magnetite in float, you are in the right ground. Typical habit: granular, nodular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find nullaginite on the map
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