Bunnoite is a rare nickel sulfate hydrate typically found as a secondary mineral in the oxidation zones of nickel-bearing ore deposits. It occurs as thin, yellow, platy crystals that are prone to dehydration, making careful storage in a dry environment essential for collectors.
Is this bunnoite?
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 bunnoite with a known reference. Bunnoite sits at Mohs 1-2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bunnoite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Bunnoite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: yellow, orange-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, granular aggregates.
Often confused with
Bunnoite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Bunnoite leaves yellow, Retgersite leaves white; luster reads resinous on Bunnoite and vitreous on Retgersite.
How to tell apart: Streak differs — Bunnoite leaves yellow, Morenosite leaves white; luster reads resinous on Bunnoite and vitreous on Morenosite.
Often found alongside bunnoite
Minerals reported to co-occur with bunnoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NiSO₄·6H₂O
- Mohs hardness
- 1-2
- Density
- 2.8 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Granular Aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Nickel-rich Sulfide Deposits
- Typical price
- $20-100 per specimen
Where rockhounds find bunnoite
Classic worldwide localities
- Bunno, Japan
- various mine dumps worldwide
Field-hunting tip
Look in oxidized zones of nickel-rich sulfide deposits country — that is the host setting where bunnoite typically forms. If you start seeing morenosite, retgersite, nickel-bearing sulfides in float, you are in the right ground. Field specimens usually show a platy crystals, granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bunnoite on the map
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