Clinoatacamite is a monoclinic polymorph of the copper oxychloride Cu₂(OH)₃Cl. It is typically found in the oxidized zones of copper deposits, often appearing as distinct green, tabular crystals or crusts that are visually indistinguishable from other members of the atacamite group without laboratory analysis.
Is this clinoatacamite?
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 clinoatacamite with a known reference. Clinoatacamite 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. Clinoatacamite leaves a apple green streak.
- 3Read the lusterHold the specimen under a strong light. Clinoatacamite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark green, bright green, emerald green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating aggregates, massive.
Often confused with
Clinoatacamite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous on Clinoatacamite and adamantine to vitreous on Atacamite.
How to tell apart: Luster reads vitreous on Clinoatacamite and adamantine on Paratacamite.
How to tell apart: Streak differs — Clinoatacamite leaves apple green, Botallackite leaves pale green.
Often found alongside clinoatacamite
Minerals reported to co-occur with clinoatacamite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂(OH)₃Cl
- Mohs hardness
- 3
- Density
- 3.75 g/cm³
- Streak
- Apple Green
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Radiating Aggregates, Massive
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Oxidized Copper Ore Deposits
- Typical price
- $20-150 for thumbnail specimens
Where rockhounds find clinoatacamite
Classic worldwide localities
- Atacama Desert, Chile
- Burra, South Australia
- Bisbee, Arizona, USA
- Lavrion, Greece
Field-hunting tip
Look in oxidized copper ore deposits country — that is the host setting where clinoatacamite typically forms. If you start seeing chrysocolla, malachite, cuprite in float, you are in the right ground. Field specimens usually show a tabular crystals, radiating aggregates, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find clinoatacamite on the map
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