Alumoklyuchevskite is a rare copper-potassium sulfate mineral found exclusively in the volcanic fumarole deposits of the Tolbachik volcano in Russia. It typically occurs as small, elongated prismatic crystals in association with other rare fumarolic minerals.

Hardness

3-4

Mohs

Luster

Vitreous

Streak

Pale Green

Transparency

Translucent

mineralrarenull family

Alumoklyuchevskite

Hardness: 3-4
Luster: Vitreous
Streak: Pale Green
Transparency: Translucent

No image

Is this alumoklyuchevskite?

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 alumoklyuchevskite with a known reference. Alumoklyuchevskite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Alumoklyuchevskite leaves a pale green streak.
3
Read the luster
Hold the specimen under a strong light. Alumoklyuchevskite 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: prismatic crystals.

Often confused with

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

mineral

Langbeinite

Mohs 3.5-4

How to tell apart: Streak differs — Alumoklyuchevskite leaves pale green, Langbeinite leaves white.

Often found alongside alumoklyuchevskite

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

All properties

Chemical formula: K₃Cu₃AlO₂(SO₄)₄
Mohs hardness: 3-4
Density: 3.36 g/cm³
Colors: Dark Green Black
Streak: Pale Green
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Volcanic Fumaroles
Typical price: $100-500 per specimen

Where rockhounds find alumoklyuchevskite

Classic worldwide localities

Tolbachik volcano, Kamchatka, Russia

Field-hunting tip

Look in volcanic fumaroles country — that is the host setting where alumoklyuchevskite typically forms. If you start seeing piypite, lammerite, tolbachite in float, you are in the right ground. Field specimens usually show a prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify alumoklyuchevskite?+

Mohs hardness is 3-4. It typically shows a vitreous luster. The streak is pale green. Common colors include dark green, black.

Where is alumoklyuchevskite found?+

Notable localities include Tolbachik volcano, Kamchatka, Russia.

How much is alumoklyuchevskite worth?+

Typical asking prices fall in the range of $100-500 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is alumoklyuchevskite safe to handle?+

It contains toxic constituents. Contains copper and potentially harmful salts associated with volcanic fumaroles. Handle with care and wash hands after contact. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like alumoklyuchevskite?+

Alumoklyuchevskite is most often confused with Langbeinite, Euchlorine. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with alumoklyuchevskite?+

Alumoklyuchevskite commonly co-occurs with Piypite, Lammerite, Tolbachite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does alumoklyuchevskite form in?+

Alumoklyuchevskite typically forms in volcanic fumaroles. Working float back to the host body is the standard way to chase a fresh occurrence.

What is alumoklyuchevskite used for?+

Alumoklyuchevskite is used in collector.

Find alumoklyuchevskite on the map

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