Stetefeldtite and Stephanite from Belmont, Nevada, USA — Photo: Kritzolina · CC BY-SA 4.0
Stephanite
A silver-antimony sulfosalt nearly 69% silver — 'brittle silver ore' — an important ore at historic mines.
Intro adapted from Wikipedia (CC BY-SA).
Stephanite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Ag₅SbS₄.
It crystallizes in the orthorhombic crystal system (space group Cmc2_1).
Key properties: Mohs hardness 2–2.5; specific gravity 6.26; typically gray or black; Iron-black streak; Metallic luster.
IMA symbol Sph, grandfathered status — known before the IMA’s founding, named in 1845.
A late-stage mineral in hydrothermal silver deposits.
It is found associated with Proustite, acanthite, silver, tetrahedrite, galena, sphalerite, pyrite.
In honor of the Archduke Victor Stephan (1817–1867), former Mining Director of Austria.
Collections: Collector Favorites, Metals & Native Elements.