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Annabergite is a secondary mineral commonly found as an alteration product of nickel arsenides in oxidized mineral veins. It is prized by collectors for its distinctive bright apple-green color, though it is very soft and delicate to handle. It is chemically related to erythrite, which typically forms pink rather than green crystals.

Hardness
1.5-2.5
Mohs
Luster
Subadamantine, pearly on cleavages, may be dull, earthy
Streak
Pale green to white
Transparency
Transparent to translucent

Is this annabergite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch annabergite with a known reference. Annabergite sits at Mohs 1.5-2.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: pale green to white.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: subadamantine, pearly on cleavages, may be dull, earthy.
  • 4
    Match the color range
    Compare against the expected color range: apple-green, pale green, white, greenish white, gray, yellow green.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: earthy, encrustations, massive.

Often confused with

Annabergite vs. its common look-alikes, and how to tell them apart in the field.

Erythrite mineral
mineral
Erythrite
Mohs 1.5-2.5
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No image
mineral
Parabrandtite
Mohs 3-4

How to tell apart: Streak differs, so Annabergite leaves pale green to white, Parabrandtite leaves white; luster reads subadamantine, pearly on cleavages, may be dull, earthy on Annabergite and vitreous on Parabrandtite.

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Often found alongside annabergite

Minerals reported to co-occur with annabergite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
Ni₃(AsO₄)₂·8H₂O
Mohs hardness
1.5-2.5
Density
3.07 g/cm³
Colors
Apple-greenPale greenWhiteGreenish whiteGrayYellow green
Streak
Pale green to white
Luster
Subadamantine, pearly on cleavages, may be dull, earthy
Transparency
Transparent to translucent
Crystal system
Monoclinic
Crystal habit
Earthy, encrustations, massive
Cleavage
{010}, perfect; {100}, {102}, indistinct
Rarity
Uncommon
Uses
Collector
Host rock
An uncommon secondary mineral, formed by the alteration of Co–Ni-bearing arsenides and sulfides, in the oxidized zone of hydrothermal mineral deposits

Where rockhounds find annabergite

Classic worldwide localities

  • Ore Hill mine, Pacoima Canyon, Los Angeles Co., and in the Kalkar quarry, Santa Cruz, Santa Cruz Co., California, USA
  • Nickel and Lovelock mines, Table Mountain district, Churchill Co., Nevada, USA
  • Snowbird mine, Mineral Co., Montana, USA
  • Alhambra mine, Grant Co., New Mexico, USA
  • Annaberg and Schneeberg, Saxony, Germany
  • Richelsdorf, Hesse, Germany

Field-hunting tip

Where it forms: An uncommon secondary mineral, formed by the alteration of Co–Ni-bearing arsenides and sulfides, in the oxidized zone of hydrothermal mineral deposits. If you start seeing erythrite, retgersite, gersdorffite in float, you are in the right ground. Typical habit: earthy, encrustations, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify annabergite?+
Mohs hardness is 1.5-2.5. Luster: subadamantine, pearly on cleavages, may be dull, earthy. The streak is pale green to white. Common colors include apple-green, pale green, white, greenish white.
Where is annabergite found?+
Notable localities include Ore Hill mine, Pacoima Canyon, Los Angeles Co., and in the Kalkar quarry, Santa Cruz, Santa Cruz Co., California, USA; Nickel and Lovelock mines, Table Mountain district, Churchill Co., Nevada, USA; Snowbird mine, Mineral Co., Montana, USA; Alhambra mine, Grant Co., New Mexico, USA; Annaberg and Schneeberg, Saxony, Germany.
Is annabergite safe to handle?+
Annabergite contains arsenic and nickel and calls for real care. Contains arsenic, a highly toxic element. Wash hands thoroughly after handling and avoid inhaling dust.
What rocks look like annabergite?+
Annabergite is most often confused with Erythrite, Parabrandtite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with annabergite?+
Annabergite commonly co-occurs with Erythrite, Retgersite, Gersdorffite, Nickeline, Maucherite, Nickel-skutterudite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does annabergite form in?+
Where it forms: An uncommon secondary mineral, formed by the alteration of Co–Ni-bearing arsenides and sulfides, in the oxidized zone of hydrothermal mineral deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is annabergite used for?+
Annabergite is used in collector.

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