Carminite - Encyclopedia
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
© Michael Förch
Carminite in the World
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