Nickelaustinite is a rare arsenate mineral belonging to the adelite group, typically forming vibrant green crusts or small acicular crystal sprays in oxidized base metal deposits. It is best identified through mineral association in the Tsumeb or Ojuela mines, where it often coats other secondary minerals like smithsonite or calcite.
Is this nickelaustinite?
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 nickelaustinite with a known reference. Nickelaustinite sits at Mohs 4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Nickelaustinite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Nickelaustinite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, yellowish-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, botryoidal, acicular crystals.
Often confused with
Nickelaustinite vs. its common look-alikes — and how to tell them apart in the field.


How to tell apart: Streak differs — Nickelaustinite leaves white, Conichalcite leaves light green.

How to tell apart: Nickelaustinite is noticeably harder (Mohs 4.5 vs. 3.5); streak differs — Nickelaustinite leaves white, Duftite leaves light green.
Often found alongside nickelaustinite
Minerals reported to co-occur with nickelaustinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca(Ni,Zn)(AsO₄)(OH)
- Mohs hardness
- 4.5
- Density
- 4.30 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, Botryoidal, Acicular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Polymetallic Ore Deposits
- Typical price
- $20-200 thumbnail
Where rockhounds find nickelaustinite
Classic worldwide localities
- Tsumeb Mine, Namibia
- Kamareza Mine, Greece
- Ojuela Mine, Mexico
- Kombat Mine, Namibia
Field-hunting tip
Look in oxidized zones of polymetallic ore deposits country — that is the host setting where nickelaustinite typically forms. If you start seeing adamite, calcite, smithsonite in float, you are in the right ground. Field specimens usually show a crusts, botryoidal, acicular crystals habit, so train your eye for that shape before scanning the outcrop.




