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Download hereGENERAL DESCRIPTION
Pyrargyrite is a silver sulfo-antimonide that belongs, like proustite (its arsenious equivalent), to the family of the "red silvers". It is found sometimes as an important silver ore. It is formed in the hydrothermal veins of medium temperature.
Its crystals, generally prismatic, sometimes as scalenohedra, can reach 6 cm.
Pyrargyrite is a photosensitive mineral: under the action of the air and light, a fine film of native silver develops on the mineral surface. The well-crystallized specimens are rare and the photosensitivity of mineral makes difficult the conservation of the samples collected in the past.
The best crystals known were extracted in Guanajuato and Fresnillo (gemmeous crystals of 5 cm) in Mexico, in Freiberg and Andreasberg in Germany, in Jachimov in the Czech Republic and the San Jenaro mine, Huancavelica in Peru.
In France, pyrargyrite was observed in Les Farges (Corrèze), the deposits of Sainte Marie-aux-Mines (Haut-Rhin) and Les Challanches (Isère). Many other mines produced pyrargyrite like in the Vosges (Urbeis, Lusse), Cantal (Labrousse, Massiac, Mauriac), Haute-Loire (La Chapelle Bertin, Chilhac, Lubilhac, Saint Pal de Senouire, Paulhaguet, Sainte-Marguerite), Brittany (Huelgoat and Pontpéan), Franche-Comté (Plancher-les-Mines), Aude (Mouthoumet, Padern), Savoy (Peisey-Nancroix).
The type is not definable because this species was already known before the conditions of deposit of the types were defined.
HISTORY : Name inspired from the Greek word [pyros] meaning "fire" and "αργuρoσ" [argyros] meaning "silver", in reference to its colour and its chemical constitution
Species described in 1831 by Ernst Frierich Glocker (1793-1858), German mineralogist
Type-locality : undefined because species already known from the Ancients
ANCIENT NAME : Mine d’argent rouge, argent antimonié sulfuré
CHEMICAL FORMULA : Ag3 Sb S3
CRYSTAL SYSTEM : Hexagonal
COLOR : Dark red
DIAPHANIETY : Translucent
LUSTER : Adamantine to metallic
STREAK : Cherry-red
MORPHOLOGIE : Prismatic crystals, scalénohedras, aggregates
HARDNESS : 2,5
CHEMICAL CLASS: 5,855
DENSITY : II - Sulfides, arsenides, antimonides and selenides
GROUP : Proustite - xanthoconite
STRUNZ CLASS BEFORE 2001 : 2/E.07-20
STRUNZ CLASS AFTER 2001 : 2.GA.05
