Chalcosiderite - Encyclopedia
Class : Phosphates, arsenates, vanadates
Subclass : Hydrated phosphates
Crystal system : Triclinic
Chemistry : CuFe6(PO4)4(OH)8 4H2O
Rarity : Very rare
Chalcosiderite is a rare copper and iron phosphate, present in the oxidation zones of polymetallic hydrothermal deposits rich in copper, along with other copper or iron phosphates (dufrenite, libethenite...) often on a matrix of goethite. It forms a series with turquoise, a mineral in which iron is replaced by aluminum. It owes its name to the Greek chalcos (copper) and sidêros (iron) because of its chemical composition. The crystals are short prisms of 3 mm maximum, grouped in bundles or encrustation of a dark green color. It is a mineral only reserved for the collection.
Chalcosiderite in the World
Chalcosiderite in France
In France, chalcosiderite is known in the tungsten and copper veins of the Montmins, near Echassières (Allier), see main photo.
Twinning and special forms
Fakes and scams
No fake recorded for this mineral species.
Hardness : 4.5
Density : 3.22
Fracture : Undetermined
Streak : Green
TP : Transparent to translucent
IR : 1.775 to 1.844
Birefringence : 0.069
Optical character : Biaxial -
Pleochroism : Not visible
Fluorescence : None
Solubility : Hydrochloric acid
Magnetism : None
Radioactivity : None