Pseudomalachite

phosphate

hydrothermal

Formula: Cu5(PO4)2(OH)4
Anhydrous phosphate containing hydroxyl
Forms a series with cornwallite
Specific gravity: 4.35
Hardness: 4½ to 5
Streak: Blue-green
Colour: Blue-green, green, dark green, green-black; green to bluish green in transmitted light.
Solubility: Soluble in acids
Environments:

Hydrothermal environments

Pseudomalachite is a secondary mineral found in the oxidised zone of hydrothermal copper ore deposits, associated with libethenite, malachite, cornetite, chrysocolla, tenorite, pyromorphite and chalcedony (Dana, Mindat, HOM).

At Broken Hill, New South Wales, Australia, pseudomalachite has been found as coatings on garnet sandstone, associated with libethenite and azurite (AJM 3.1.50).

At Girilambone mine, New South Wales, Australia, pseudomalachite is associated with malachite and libethenite, and also with azurite (AJM 11.2.97-98).

At Northparkes, New South Wales, Australia, pseudomalachite is associated with libethenite (AJM 10.2.55).

At the Desolation prospect, Queensland, Australia, pseudomalachite is associated with malachite and chrysocolla, and sometimes with libethenite (AJM 17.2.86).

At the Chino mine, New Mexico, USA, pseudomalachite is restricted to the oxidised portion of the orebody and is associated with chrysocolla, apatite, and libethenite (R&M 84.6.498).

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