Anthonyite is a rare copper halide mineral typically found as small, thin, blue to blue-green platy crystals or rosettes. It occurs primarily in the oxidized zones of copper-rich hydrothermal deposits and is prized by micro-mineral collectors for its delicate habit.
Is this anthonyite?
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 anthonyite with a known reference. Anthonyite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Anthonyite leaves a pale blue streak.
- 3Read the lusterHold the specimen under a strong light. Anthonyite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: blue, blue-green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, flakes, rosettes.
Often confused with
Anthonyite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Connellite is the harder of the two (Mohs 3 vs. 2); luster reads pearly on Anthonyite and vitreous on Connellite.
How to tell apart: Paratacamite is the harder of the two (Mohs 3 vs. 2); streak differs — Anthonyite leaves pale blue, Paratacamite leaves apple green; luster reads pearly on Anthonyite and adamantine on Paratacamite.
How to tell apart: Atacamite is the harder of the two (Mohs 3-3.5 vs. 2); streak differs — Anthonyite leaves pale blue, Atacamite leaves apple green; luster reads pearly on Anthonyite and adamantine to vitreous on Atacamite.
Often found alongside anthonyite
Minerals reported to co-occur with anthonyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu(OH,Cl)₂·nH₂O
- Mohs hardness
- 2
- Density
- 3.31 g/cm³
- Colors
- Streak
- Pale Blue
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Flakes, Rosettes
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper Deposits
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find anthonyite
Classic worldwide localities
- Big Indian mine, Arizona, USA
- Planet mine, Arizona, USA
- Chuquicamata, Chile
Field-hunting tip
Look in oxidized zones of copper deposits country — that is the host setting where anthonyite typically forms. If you start seeing cuprite, chrysocolla, tenorite in float, you are in the right ground. Field specimens usually show a platy crystals, flakes, rosettes habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find anthonyite on the map
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