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

Beautiful specimens come from polymetallic veins of English Cornwall (Linkinhoren, Saint Austell), Germany (Siegen, Schneckenstein, and the pegmatite of Hagendorf, Bavaria). Good specimens are also found in the copper mines of Bisbee in Arizona.

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

No twin known for this mineral species.

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