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.
Is this kozyrevskite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch kozyrevskite with a known reference. Kozyrevskite sits at Mohs ~3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very light green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: bright grass-green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals.
Often confused with
Kozyrevskite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Kozyrevskite is noticeably harder (Mohs ~3.5 vs. 2-2.5); streak differs, so Kozyrevskite leaves very light green, Lanarkite leaves white; luster reads vitreous on Kozyrevskite and adamantine to resinous, pearly on cleavage surfaces on Lanarkite.
How to tell apart: Kozyrevskite is noticeably harder (Mohs ~3.5 vs. 2.5); streak differs, so Kozyrevskite leaves very light green, Piypite leaves yellowish green.
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
- ~3.5
- Density
- 4.934 g/cm³
- Colors
- Bright grass-green
- 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
- As complex incrustations on the surface of basalt scoria or in open pockets
Where rockhounds find kozyrevskite
Classic worldwide localities
- Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia
Field-hunting tip
Where it forms: As complex incrustations on the surface of basalt scoria or in open pockets. If you start seeing ericlaxmanite, urusovite, lammerite in float, you are in the right ground. Typical habit: prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find kozyrevskite on the map
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