Botallackite is a rare copper halide mineral typically forming as thin, platy crystals in oxidized copper deposits. It is best identified by its bright green color and association with other secondary copper minerals in historic mining districts like Cornwall.
Is this botallackite?
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 botallackite with a known reference. Botallackite 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. Botallackite leaves a pale green streak.
- 3Read the lusterHold the specimen under a strong light. Botallackite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: bright green, bluish green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, crusts, radial aggregates.
Often confused with
Botallackite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Botallackite leaves pale green, Atacamite leaves apple green; luster reads vitreous on Botallackite and adamantine to vitreous on Atacamite.
How to tell apart: Streak differs — Botallackite leaves pale green, Paratacamite leaves apple green; luster reads vitreous on Botallackite and adamantine on Paratacamite.
How to tell apart: Streak differs — Botallackite leaves pale green, Malachite leaves light green.
Often found alongside botallackite
Minerals reported to co-occur with botallackite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₂Cl(OH)₃
- Mohs hardness
- 3
- Density
- 3.59 g/cm³
- Colors
- Streak
- Pale Green
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Crusts, Radial Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Copper Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find botallackite
Classic worldwide localities
- Botallack Mine, Cornwall, England
- Chile
- Germany
- Italy
Field-hunting tip
Look in oxidized copper deposits country — that is the host setting where botallackite typically forms. If you start seeing connellite, cuprite, limonite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find botallackite on the map
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