Zaratite is a rare secondary nickel mineral typically found as emerald-green crusts or botryoidal coatings on chromite-bearing serpentine. It is best identified by its vibrant color and association with nickel sulfides, though true zaratite specimens are often difficult to distinguish from other amorphous nickel-bearing minerals without chemical analysis.
Is this zaratite?
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 zaratite with a known reference. Zaratite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to greasy.
- 4Match the color rangeCompare against the expected color range: emerald green.
- 5Look at form & habitCrystal system: cubic. Typical habit: encrustations, mammillary, massive.
Often confused with
Zaratite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Zaratite is noticeably harder (Mohs 3.5 vs. 2-2.5); streak differs, so Zaratite leaves light green, Morenosite leaves pale green to white.
How to tell apart: Bunsenite is the harder of the two (Mohs 5.5 vs. 3.5); streak differs, so Zaratite leaves light green, Bunsenite leaves brownish black.
How to tell apart: Streak differs, so Zaratite leaves light green, Malachite leaves pale green; luster reads vitreous to greasy on Zaratite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
Often found alongside zaratite
Minerals reported to co-occur with zaratite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₃(CO₃)(OH)₄·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.57-2.69 g/cm³
- Colors
- Streak
- Light green
- Luster
- Vitreous to greasy
- Transparency
- Transparent to translucent
- Crystal system
- Cubic
- Crystal habit
- Encrustations, mammillary, massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon secondary mineral formed by alteration of chromite, pentlandite, pyrrhotite, and millerite in serpentinites and ultramafic rocks
Where rockhounds find zaratite
Classic worldwide localities
- Pennsylvania, from Wood’s, Carter’s, and Low’s mines, Texas, Lancaster Co., and at Phillip’s chrome mine, West Nottingham, Chester Co., USA
- Igdlokunguak, Greenland
- Talmessi mine, 35 km west of Anarak, Iran
- Dun Mountain, Nelson, New Zealand
- Lord Brassey mine, Heazlewood, Tasmania, Australia
- Hagdale quarry, Unst, Shetland Islands, Scotland
Field-hunting tip
Where it forms: An uncommon secondary mineral formed by alteration of chromite, pentlandite, pyrrhotite, and millerite in serpentinites and ultramafic rocks. If you start seeing brucite, hydromagnesite, calcite in float, you are in the right ground. Typical habit: encrustations, mammillary, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify zaratite?+
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Find zaratite on the map
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