Nickeline is a striking metallic nickel arsenide recognized by its characteristic pale copper-red color that often tarnishes to a darker greyish-brown. It is typically found in massive or reniform habits within hydrothermal vein systems associated with other nickel and cobalt minerals.
Is this nickeline?
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 nickeline with a known reference. Nickeline sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Nickeline leaves a brownish-black streak.
- 3Read the lusterHold the specimen under a strong light. Nickeline typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: pale copper-red, light bronze.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: massive, reniform, columnar, rarely as hexagonal crystals.
Often confused with
Nickeline vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Nickeline leaves brownish-black, Breithauptite leaves red-brown.
How to tell apart: Streak differs — Nickeline leaves brownish-black, Pyrrhotite leaves dark grey to black.
How to tell apart: Streak differs — Nickeline leaves brownish-black, Skutterudite leaves black.
Often found alongside nickeline
Minerals reported to co-occur with nickeline. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NiAs
- Mohs hardness
- 5-5.5
- Density
- 7.3-7.7 g/cm³
- Streak
- Brownish-black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Hexagonal
- Crystal habit
- Massive, Reniform, Columnar, Rarely as Hexagonal Crystals
- Cleavage
- Indistinct
- Rarity
- Uncommon
- Uses
- Collector, Ore of Nickel
- Host rock
- Hydrothermal Veins, Nickel-cobalt-silver Deposits
- Typical price
- $10-100 per specimen depending on size and association
Where rockhounds find nickeline
Classic worldwide localities
- Cobalt, Ontario, Canada
- Erzgebirge, Germany
- Schladming, Austria
- Norilsk, Russia
Field-hunting tip
Look in hydrothermal veins, nickel-cobalt-silver deposits country — that is the host setting where nickeline typically forms. If you start seeing arsenopyrite, cobaltite, silver in float, you are in the right ground. Field specimens usually show a massive, reniform, columnar, rarely as hexagonal crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find nickeline on the map
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