Jamborite is a rare nickel-bearing mineral that typically forms as delicate, fibrous crusts or earthy coatings on sulfide ore surfaces. It is most commonly found in the oxidation zones of nickel-rich hydrothermal deposits, often appearing as a weathering product of millerite.
Is this jamborite?
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 jamborite with a known reference. Jamborite sits at Mohs 2, 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: dull.
- 4Match the color rangeCompare against the expected color range: green.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: fibrous, lamellar, microscopic crystals.
Often confused with
Jamborite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Gartrellite is the harder of the two (Mohs 4.5 vs. 2); streak differs, so Jamborite leaves light green, Gartrellite leaves bright yellow; luster reads dull on Jamborite and chalky on Gartrellite.
How to tell apart: Bunsenite is the harder of the two (Mohs 5.5 vs. 2); streak differs, so Jamborite leaves light green, Bunsenite leaves brownish black; luster reads dull on Jamborite and vitreous on Bunsenite.
How to tell apart: Streak differs, so Jamborite leaves light green, Annabergite leaves pale green to white; luster reads dull on Jamborite and subadamantine, pearly on cleavages, may be dull, earthy on Annabergite.
Often found alongside jamborite
Minerals reported to co-occur with jamborite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₁₋₀.₇Co₀₋₀.₃(OH)₁.₇(SO₄)₀.₃·(H₂O)₀.₇
- Mohs hardness
- 2
- Density
- 2.67 g/cm³
- Colors
- Streak
- Light green
- Luster
- Dull
- Transparency
- Semitransparent
- Crystal system
- Hexagonal
- Crystal habit
- Fibrous, lamellar, microscopic crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In small cavities in ophiolitic rocks (Italy); in serpentinites (Shinshiro, Japan)
Where rockhounds find jamborite
Classic worldwide localities
- Sterling mine, Antwerp, Jefferson Co., New York, USA
- Volstead quarry, Hillview, Greene Co., Illinois, USA
- Hall’s Gap, Lincoln Co., Kentucky, USA
- Ca’dei Ladri and Monteacuto Ragazza, 50 km southwest of Bologna, and Catelluccio di Moscheda, Modena, Emilia-Romagna, Italy
- Found at Shinshiro, Aichi Prefecture, Japan
Field-hunting tip
Where it forms: In small cavities in ophiolitic rocks (Italy); in serpentinites (Shinshiro, Japan). If you start seeing millerite, calcite, dolomite in float, you are in the right ground. Typical habit: fibrous, lamellar, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find jamborite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
