Aerugite is a rare nickel arsenate mineral that typically forms as minute, bright green hexagonal plates. It is primarily found in old mining districts in Saxony, Germany, often associated with other nickel-bearing secondary minerals. Due to its extreme rarity, it is highly sought after by advanced mineral collectors specializing in rare species.
Is this aerugite?
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 aerugite with a known reference. Aerugite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green, pale blue-green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: green, deep blue green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: encrustations, euhedral crystals, massive.
Often confused with
Aerugite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Aerugite is noticeably harder (Mohs 4 vs. 1.5-2.5); luster reads vitreous on Aerugite and subadamantine, pearly on cleavages, may be dull, earthy on Annabergite.
How to tell apart: Bunsenite is the harder of the two (Mohs 5.5 vs. 4); streak differs, so Aerugite leaves pale green, pale blue-green, Bunsenite leaves brownish black.
Often found alongside aerugite
Minerals reported to co-occur with aerugite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ni₈.₅(AsO₄)₂AsO₈
- Mohs hardness
- 4
- Density
- 5.85 g/cm³
- Colors
- GreenDeep blue green
- Streak
- Pale green, pale blue-green
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Trigonal
- Crystal habit
- Encrustations, euhedral crystals, massive
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral in hydrothermal Ni–As–U ore deposits
Where rockhounds find aerugite
Classic worldwide localities
- Johanngeorgenstadt, Saxony, Germany
- South Terras mine, St. Stephen-in-Brannel, Cornwall, England
Field-hunting tip
Where it forms: A rare secondary mineral in hydrothermal Ni–As–U ore deposits. If you start seeing bismuth, bunsenite, xanthiosite in float, you are in the right ground. Typical habit: encrustations, euhedral crystals, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify aerugite?+
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Find aerugite on the map
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