Kozyrevskite is a rare copper arsenate that forms prismatic crystals. It occurs in complex incrustations on the surface of basalt scoria or in open pockets. Associated minerals include ericlaxmanite, urusovite and lammerite. It was first described from Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia.

Hardness
2
Mohs
Luster
Vitreous
Streak
Very Light Green
Transparency
Transparent

Is this kozyrevskite?

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 kozyrevskite with a known reference. Kozyrevskite 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. Kozyrevskite leaves a very light green streak.
  • 3
    Read the luster
    Hold the specimen under a strong light. Kozyrevskite typically shows a vitreous luster.
  • 4
    Match the color range
    Compare against the expected color range: bright grass-green, light yellowish green.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: prismatic crystals.

Often confused with

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

Often found alongside kozyrevskite

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

All properties

Chemical formula
Cu₄O(AsO₄)₂
Mohs hardness
2
Density
4.934 g/cm³
Streak
Very Light Green
Luster
Vitreous
Transparency
Transparent
Crystal system
Orthorhombic
Crystal habit
Prismatic Crystals
Cleavage
Perfect On {100} and {001}
Rarity
Rare
Uses
Collector
Host rock
Fumarole Deposits

Where rockhounds find kozyrevskite

Classic worldwide localities

  • Tolbachik Volcano, Kamchatka Peninsula, Russia

Field-hunting tip

Look in fumarole deposits country, the host setting where kozyrevskite typically forms. If you start seeing tolbachite, tenorite, piypite 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 kozyrevskite?+
Mohs hardness is 2. It typically shows a vitreous luster. The streak is very light green. Common colors include bright grass-green, light yellowish green.
Where is kozyrevskite found?+
Notable localities include Tolbachik Volcano, Kamchatka Peninsula, Russia.
Is kozyrevskite safe to handle?+
It contains toxic constituents. Contains arsenic and copper, which are toxic if ingested or inhaled as dust. Wash hands thoroughly after handling and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.
What rocks look like kozyrevskite?+
Kozyrevskite is most often confused with Lanarkite, Piypite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with kozyrevskite?+
Kozyrevskite commonly co-occurs with Tolbachite, Tenorite, Piypite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does kozyrevskite form in?+
Kozyrevskite typically forms in fumarole deposits. Working float back to the host body is the standard way to chase a fresh occurrence.
What is kozyrevskite used for?+
Kozyrevskite is used in collector.

Find kozyrevskite on the map

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