Images
Formula: CuFe3+6(PO4)4(OH)8.4H2O
Hydrated phosphate containing hydroxyl, turquoise group and forms
a series with
turquoise
Crystal System: Triclinic
Specific gravity: 3.22 measured, 3.28 calculated
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
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).
Localities
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).
Chalcosiderite from Lake Boga - Image
At the Ste Barbe vein (Les Montmins), Montmins mining district, Échassières, Vichy, Allier, Auvergne-Rhône-Alpes,
France, brown to black botryoidal goethite occurs on light green striped
chalcosiderite crystals, and both on quartz
(Mindat photo).
Chalcosiderite from the Ste Barbe vein -
Image
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).
Chalcosiderite from the West Phoenix Mine -
Image
At the Gunheath china clay pit, Cornwall, England, UK, chalcosiderite is associated with
dufrénite, cyrilovite and
leucophosphite (HOM).
Chalcosiderite from the Gunheath china clay
pit - Image
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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