Coparsite is a rare copper-chloride mineral discovered in the volcanic fumaroles of the Tolbachik volcano in Russia. It typically forms small, dark green tabular crystals within salt-rich volcanic crusts and is highly prized by advanced mineral collectors.
Is this coparsite?
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 coparsite with a known reference. Coparsite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: metallic.
- 4Match the color rangeCompare against the expected color range: black, dark gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: inclusions, microscopic crystals.
Often confused with
Coparsite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Coparsite leaves brown, Atacamite leaves apple-green; luster reads metallic on Coparsite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs, so Coparsite leaves brown, Paratacamite leaves green; luster reads metallic on Coparsite and vitreous on Paratacamite.
Often found alongside coparsite
Minerals reported to co-occur with coparsite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄O₂AsO₄Cl
- Mohs hardness
- 3
- Density
- 4.76 g/cm³
- Streak
- Brown
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Inclusions, microscopic crystals
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As sublimates near a volcanic fumarole vent and included within euchlorine
Where rockhounds find coparsite
Classic worldwide localities
- Found in the Yadovitaya (= poisonous) Fumarole in the North Breach of the Main Tolbachik fissure eruption of 1975-1976, Kamchatka Peninsula, Russia (type locality)
Field-hunting tip
Where it forms: As sublimates near a volcanic fumarole vent and included within euchlorine. If you start seeing euchlorine, tolbachite, kamchatkite in float, you are in the right ground. Typical habit: inclusions, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify coparsite?+
Where is coparsite found?+
Is coparsite safe to handle?+
What rocks look like coparsite?+
What minerals are found with coparsite?+
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Find coparsite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
