Miargyrite

Miargyrite Locality: San Genaro Mine, Castrovirreyna District, Castrovirreyna Province, Huancavelica Department, Peru Size: small cabinet, 6.1 x 4.2 x 2.7 cm © Rob Lavinsky / iRocks

Chemical Formula: AgSbS2
Locality: Braunsdorf, Freiberg, Sachsen (Saxony), Germany.
Name Origin: From the Greek, meyon, “smaller” and argyros, “silver.” in allusion to the lessor silver content of the mineral.

Miargyrite is a mineral, a sulfide of silver and antimony with the formula AgSbS2. It is a dimorph of cuboargyrite. Originally discovered in the Freiberg district of Germany in 1824, it has subsequently been found in many places where silver is mined. It usually occurs in low temperature hydrothermal deposits. and forms black metallic crystals which may show a dark red internal reflection. The streak is also red.

Miargyrite is named from the Greek meyon, “smaller” and argyros, “silver,” as its silver content is lower than most silver sulfides.

History

Discovery date : 1829
Town of Origin : BRAUNSDORF, FREIBERG, SAXE
Country of Origin : ALLEMAGNE

Optical properties

Optical and misc. Properties : Translucent to Subopaque
Reflective Power: 26,3-38,7% (580)
Refractive Index : from 2,72 to 2,73

Physical Properties

Cleavage: {010} Imperfect
Color:     Steel gray, Lead gray, Blackish red, Reddish gray.
Density: 5.1 – 5.3, Average = 5.19
Diaphaneity: Translucent to Subopaque
Fracture: Brittle – Generally displayed by glasses and most non-metallic minerals.
Hardness: 2-2.5 – Gypsum-Finger Nail
Luminescence: Non-fluorescent.
Luster: Sub Metallic
Streak: cherry red

Photos :

Miargyrite, Pyrargyrite 5.7×4.8×5.2 cm San Genaro Mine Castrovirreyna, Huancavelica Peru Copyright © David K. Joyce Minerals
Miargyrite micro cm Van Silver Mine nr. Whistler British Columbia, Canada Copyright © David K. Joyce Minerals
Neue Hoffnung Gottes Mine, Bräunsdorf, Freiberg District, Erzgebirge, Saxony, Germany © Stephan Wolfsried
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