Silvery crystal aggregates and crystals of the very rare minerals paracostibite and costibite, from Getön Silver Mine, Persberg, Filipstad, Värmland County, Sweden. Both minerals occur together in the TL. Associated to golden chalcopyrite. Paracostibite-costibite in visible crystals like in the photo is very rare. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Costibite
Costibite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula CoSbS.
It crystallizes in the orthorhombic crystal system (space group Pn2_1m). It is a member of the Löllingite structural group.
Key properties: specific gravity 6.89; Metallic luster.
IMA symbol Csb, IMA status: approved, named in 1969.
Intimately intergrown with other hydrothermal sulfides (Broken Hill, Australia); in Pb–Zn–Cu–Ag ore deposits remobilized by hydrothermal solutions from later granite emplacement (Bergslagen, Sweden).
It is found associated with Löllingite, willyamite, dyscrasite, ullmannite, pyrargyrite (Broken Hill, Australia); nisbite, paracostibite, chalcopyrite, bismuth, pyrrhotite, galena.
The name refers to CObalt and antimony, STIBium, in its composition.