CARMINITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous arsenates
    Crystal system : Orthorhombic
    Chemistry : PbFe2(AsO4)2(OH)2
    Rarity : Uncommon

Carminite is a fairly rare lead and iron arsenate, present in the oxidation zone of lead and arsenic mineralization, where it notably rubs shoulders with scorodite, beudantite and cerussite. Its appearance requires the presence of arsenopyrite in the sulfide ore. It was named so because of its carmine red color. It forms characteristic elongated lamellar crystals, 2 cm at most, as well as acicular crystals grouped in fibroradiated spherical aggregates or tufts. Its color, not always crimson, is frequently red-brown to slightly orange-red.

Main photo : Carminite from Montmins, Echassières, Allier, France © Sylvano Iob

Carminite from Cap Garonne, Var, France © Pascal Chollet
Carminite from Montmins, Echassières, Allier, France © Philippe Font
Carminite from Rompas, Nièvre, France © Yannick Vessely
Carminite des Montmins, Echassières, Allier, France
© Michael Förch

Carminite in the World

The most beautiful known specimens of carminite are 2 cm lamellar to acicular crystals from the Ojuela Mine, near Mapimi (Mexico), and Tsumeb (Namibia). Beautiful crystals also come from the veins of English Cornwall, notably Calstock, and the Rhine veins of Horhausen and Bad Ems (Germany). Carminite is also present in several deposits in Utah, Nevada and Australia.

Carminite in France

In France, carminite is known at Cap Garonne (Var), as well as at Rabasse (Hérault), Les Rompas (Nièvre) and Puy-les-Vignes (Haute-Vienne). Very beautiful crystallizations were discovered at Echassières (Allier).

Twinning

No twin known for this mineral species.

Fakes and treatments

No fake identified for this mineral species.


Hardness : 3.5
Density : 5.03 to 5.18
Fracture : -
Streak : Red-yellow

TP : Translucent to transparent
RI : 2.050 to 2.080
Birefringence : 0.010
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : Nitric or hydrochloric acid


Magnetism : None
Radioactivity : None