GUDMUNDITE

    Class : Sulfides and sulfosalts
    Subclass : Sulfides
    Crystal system : Monoclinic
    Chemistry : FeSbS
    Rarity : Rare

Gudmundite is an accessory sulfide of antimony hydrothermal veins. It is the antimonium equivalent of arsenopyrite, gudmundite is much rarer than the latter. It owes its name to its location of discovery : Gudmundstorp (Sweden). It often appears in stubby prisms, frequently twinned, or massive, from a silvery white to light steel gray color.

Main photo : Gudmundite from Uranium Mine No. 19, Dubenec, Príbram District, Czech Republic © Christophe Boutry

Gudmundite in the World

Gudmundite is known in quite many localities. Scandinavia provided fine specimens, notably Gudmunstorp and Boliden (Sweden), and Kalliolampi (Finland). Various mining deposits in Canada (Hemlo, Red Lake, Lake Nicolet) also contain gudmundite, as well as the antimony deposit of Pezinok (Slovakia), the lead and silver deposit of Silvermines (Ireland) and the uranium deposit from Pribram (Czech Republic).

Greenockite in France

In France, gudmundite is known at the La Rodde mine near Ally (Haute-Loire), in Bodennec (Finistère). It is also reported in Chanac-les-Mines (Corrèze) and Arraus (Haute-Garonne).

Twinning

Twins are known on {101} by penetration and contact and form crosses and butterflies.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 5.5 to 6
Density : 6,72
Fracture : Undeterminated
Streak : Black

TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None