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

Mohs

Luster

Vitreous

Streak

Pale Green

Transparency

Translucent

mineralrare

Aleutite

Hardness: 2
Luster: Vitreous
Streak: Pale Green
Transparency: Translucent

No image

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.

mineral

Lammerite

Mohs 3.5

How to tell apart: Lammerite is the harder of the two (Mohs 3.5 vs. 2); streak differs, so 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 Green Black
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, 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.