Formula: CuFe3+6(PO4)4(OH)8.4H2O
Hydrated phosphate containing hydroxyl, turquoise group and forms a series with turquoise
Specific gravity: 3.22
Hardness: 4½
Streak: pale green to greenish to white
Colour: dark green to apple-green
Solubility: Soluble with difficulty in hydrochloric acid
Common impurities: Al

Hydrothermal environments

Chalcosiderite is an uncommon mineral occurring in the oxidised zone of some hydrothermal deposits (Mindat, Webmin, HOM). Associated minerals include crandallite, cyrilovite, dufrénite, leucophosphite, libethenite, pseudomalachite, saléeite, sampleite, and torbernite (Mindat).


The Lake Boga granite, Lake Boga, Swan Hill Rural City, Victoria, Australia, is a very large intrusion formed about 365 million years ago. The entire outcrop of the granite is overlain by sediments in places up to several hundred meters thick. The sole exposure into the granite is the Lake Boga quarry, where the sediment is only a few metres thick. The uppermost levels of the granite exhibit aplite veins, pods of pegmatite, and numerous miarolitic cavities, features that are characteristic of the uppermost levels of a granite magma intruded to shallow crustal levels (R&M 97.1.28-32).
Chalcosiderite at this locality is associated with sampleite, libethenite, crandallite, cyrilovite, pseudomalachite, saléeite, torbernite and ulrichite (HOM).

There are two co-type Localities, the Hollertszug Mine, Dermbach, Herdorf, Altenkirchen, Rhineland-Palatinate, Germany and the Phoenix United Mine, Minions, Linkinhorne, Cornwall, England, UK.

At the West Phoenix mine, Cornwall, England, chalcosiderite is associated with goethite and dufrénite (HOM).

At the Gunheath china clay pit, Cornwall, England, UK, chalcosiderite is associated with dufrénite, cyrilovite and leucophosphite (HOM).

At the Old Reliable Mine, Copper Creek, Bunker Hill District, Pinal county, Arizona, USA, chalcosiderite is found as rare, pale green crystals coating other minerals in cavities. A few specimens have been found where it is encrusting or replacing crystals of apatite (R&M 96.2.153).

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