Pseudomalachite is a secondary copper phosphate mineral known for its distinctive dark green botryoidal and radiating fibrous crusts. It is visually similar to malachite but can be distinguished by its slightly harder nature and distinct occurrence in phosphate-bearing copper deposits.
Is this pseudomalachite?
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 pseudomalachite with a known reference. Pseudomalachite sits at Mohs 4.5-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green to pale bluish green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous.
- 4Match the color rangeCompare against the expected color range: dark green, blue green, green, black green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, reniform, crusts, or radiating fibrous aggregates.
Often confused with
Pseudomalachite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to resinous on Pseudomalachite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.
How to tell apart: Streak differs, so Pseudomalachite leaves pale green to pale bluish green, Chrysocolla leaves white when pure.
How to tell apart: Streak differs, so Pseudomalachite leaves pale green to pale bluish green, Veszelyite leaves green to white.
Often found alongside pseudomalachite
Minerals reported to co-occur with pseudomalachite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₅(PO₄)₂(OH)₄
- Mohs hardness
- 4.5-5
- Density
- 4.15-4.35 g/cm³
- Streak
- Pale green to pale bluish green
- Luster
- Vitreous to resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, reniform, crusts, or radiating fibrous aggregates
- Cleavage
- Perfect on {100}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- A secondary mineral in the oxidized zone of hydrothermal copper deposits
Where rockhounds find pseudomalachite
Classic worldwide localities
- Perkiomen and Ecton mines, Montgomery Co., Pennsylvania, USA
- Empire-Nevada mine, Yerington district, Lyon Co., USA
- Lone Star mine, near Safford, Graham Co., from Harquehala, La Paz Co., Arizona, USA
- Ehl, near Linz, and Virneberg, near Rheinbreitbach, Rhineland-Palatinate, Germany
- L’ubietová, near Baňská Bystrica (Libethen, near Neusohl), Slovakia
- Nizhni Tagil and Bogoslovsk, Ural Mountains, Russia
Field-hunting tip
Where it forms: A secondary mineral in the oxidized zone of hydrothermal copper deposits. If you start seeing libethenite, malachite, cornetite in float, you are in the right ground. Typical habit: botryoidal, reniform, crusts, or radiating fibrous aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find pseudomalachite on the map
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