Aramayoite Locality: Animas Mine, Atocha-Quechisla District, Sud Chichas Province , Potosí Department , Bolivia ( Locality at mindat.org ) One of the rarest silver minerals that isn't just found in microscopic amounts in polished sections. Usually seen, when seen at all, in very small cleavages. This is an outstanding specimen from the original locality, with much of the specimen consisting of large thick xl plates of aramayoite. Specimens like this, likely found in the 1920s, rarely come on the market. It is, according to Mark, unprecedented in quality since the discovery of the mineral in 1926. It was an abberant crystal that turned up in an old collection purchased by Cal Graeber some years ago. True, it is a crude crystal that fades out at the base, but it has a decent termination and clear faces, and is of rather high import so a few blemishes can be forgiven in that regard. 2.3 x 1.5 x 1.2 cm — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Aramayoite
A silver-antimony-bismuth sulfosalt from Sud Chichas in Bolivia's Potosí department.
Intro adapted from Wikipedia (CC BY-SA).
Aramayoite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Ag₃Sb₂(Bi,Sb)S₆.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Aramayoite structural group.
Key properties: Mohs hardness 2.5; specific gravity 5.602; Black to red-brown streak; Brilliant metallic luster.
IMA symbol Ary, grandfathered status — known before the IMA’s founding, named in 1926.
Rare, typically in vein-controlled hydrothermal Sn–Ag ores.
It is found associated with Tetrahedrite, miargyrite, stannite, pyrite, quartz.
The name refers to Felix Avelino Aramayo (1846–1929), former Managing Director of the Compagnie Aramayo de Mines en Bolivie.