Stützite
A silver telluride described in 1951 from a museum specimen found at Sacarîmb, Romania.
Intro adapted from Wikipedia (CC BY-SA).
Stützite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Ag₅₋ₓTe₃ (x = 0.24-0.36).
It crystallizes in the hexagonal crystal system (space group P6/mmm).
Key properties: Mohs hardness 3.5; specific gravity 8; Metallic. Anisotropism: Moderate, in gray reddish brown-blue. R1 –R2: (400) 41.2–42.9, (420) 41.2–42.5 luster.
IMA symbol Stz, IMA status: approved, named in 1878.
Occurs as replacement masses in hydrothermal deposits in association with other tellurides and sulfides.
It is found associated with Sylvanite, hessite, altaite, petzite, empressite, tellurium, gold, galena, sphalerite, colusite, tetrahedrite–tennantite, pyrite.
The mineral was named to honor Andreas Xavier Stütz (1747–1806), mineralogist of Vienna, Austria.