Andorite - Encyclopedia

    Class : Sulfides and sulfosalts
    Subclass : Sulfosalts
    Crystal System : Orthorhombic
    Chemistry : PbAgSb3S6
    Rarity : Very rare

Andorite is a mineral of hydrothermal origin present in polymetallic veins of high and medium temperature. This term was recently renamed (2022): it actually includes two minerals, quatrandorite and senandorite. It is a mineral that owes its name to the Hungarian aristocrat and mineralogist Andor von Semsey. Andorite forms squat prismatic crystals up to 3 cm striated parallel to the elongation according to [001] and larger flattened tabular crystals according to {100}. She has no cleavage. Andorite has a metallic luster, a dark steel gray color fading to yellowish with iridescence. Its chemistry with Pb, Sb, Ag (and often Cu) reflects the presence of many metals in hydrothermal fluids. The procession of accompanying minerals is therefore very large : galena, stibnite, franckeite, pyrargyrite, arsenopyrite, pyrite, etc... It is an accessory ore of silver, mainly on Bolivian deposits.

Andorite in the World

The most beautiful known samples are strongly striated flattened crystals of 8 cm implanted on pyrite or arsenopyrite, which come from Oruro (Bolivia). But other Bolivian mines provided quality samples. In Europe, the most beautiful crystals, measuring 20 mm by 2 mm, were extracted from the Romanian mine of Baia Sprie.
Photos : Andorite from San José Mine, Oruro, Cercado Province, Oruro, Bolivia - © Brian Kosnar - Mineral Classics

Andorite in France

In France, sub-centimetric masses of andorite (senandorite) accompany stibine, sphalerite and tetrahedrite in the small antimony vein of Borderies (Puy-de-Dôme).


No twin report for this mineral species.

Fakes and treatments

No fake reported for this species.

Hardness : 3.5
Density : 5.35
Fracture : Conchoidal
Trace : Black

TP : Opaque
RI : Not measurable
Birefringence : Not measurable
Optical character : Not measurable
Pleochroism : None
Fluorescence : None

Solubility : Hydrochloric acid

Magnetism : None
Radioactivity : None