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Aleutite is an extremely rare copper arsenate mineral found as a result of volcanic fumarole activity. It typically occurs as tiny, dark, tabular crystals or crusts within specific high-temperature environments in the Kamchatka region.

Hardness
2
Mohs
Luster
Vitreous
Streak
Pale Green
Transparency
Translucent

Is this aleutite?

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 aleutite with a known reference. Aleutite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Aleutite leaves a pale green streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Aleutite typically shows a vitreous luster.
  • 4
    Match the color range
    Compare against the expected color range: dark green, black.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: tabular crystals, crusts.

Often confused with

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

Lammerite mineral
mineral
Lammerite
Mohs 3.5

How to tell apart: Lammerite is the harder of the two (Mohs 3.5 vs. 2); streak differs — Aleutite leaves pale green, Lammerite leaves light green.

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Often found alongside aleutite

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

All properties

Chemical formula
Cu₅(AsO₄)₂O₂
Mohs hardness
2
Density
4.15 g/cm³
Colors
Dark GreenBlack
Streak
Pale Green
Luster
Vitreous
Transparency
Translucent
Crystal system
Monoclinic
Crystal habit
Tabular Crystals, Crusts
Cleavage
Perfect
Rarity
Rare
Uses
Collector
Host rock
Fumarole Deposits
Typical price
$50-300 per specimen

Where rockhounds find aleutite

Classic worldwide localities

  • Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in fumarole deposits country — that is the host setting where aleutite typically forms. If you start seeing lammerite, tenorite, sylvite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify aleutite?+
Mohs hardness is 2. It typically shows a vitreous luster. The streak is pale green. Common colors include dark green, black.
Where is aleutite found?+
Notable localities include Tolbachik volcano, Kamchatka, Russia.
How much is aleutite worth?+
Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.
Is aleutite safe to handle?+
It contains toxic constituents. Contains arsenic and copper; wash hands thoroughly after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like aleutite?+
Aleutite is most often confused with Lammerite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with aleutite?+
Aleutite commonly co-occurs with Lammerite, Tenorite, Sylvite, Halite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does aleutite form in?+
Aleutite typically forms in fumarole deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is aleutite used for?+
Aleutite is used in collector.

Find aleutite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.

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