Stützite

Stützite
Stützite from the Moctezuma Mine, Sonora, Mexico (size:3.7 x 3.3 x 1.7 cm)
General
CategoryTelluride mineral
FormulaAg5−xTe3(with x = 0.24 to 0.36)
IMA symbolStz[1]
Strunz classification2.BA.30e
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m)
Space groupP6/mmm
Unit cella = 13.38, c = 8.45 [Å]; Z = 7
Identification
ColorDark lead-gray
Crystal habitMassive, compact, granular
CleavageNone observed
FractureSubconchoidal
TenacityBrittle
Mohs scale hardness3.5
LusterMetallic
DiaphaneityOpaque
Specific gravity8.0
Alters toTarnishes rapidly to a dark bronze to iridescence
Other characteristicsAnisotrpism in polished section: Moderate, in gray reddish brown-blue
References[2][3][4]

Stützite or stuetzite is a silvertelluride mineral with formula: Ag5−xTe3 (with x = 0.24 to 0.36)[2] or Ag7Te4.[5]

It was first described in 1951 from a museum specimen from Sacarimb, Romania. It was named for Austrian mineralogist Andreas Xaverius Stütz (1747–1806).[2][3]

It occurs with other sulfide and telluride minerals in hydrothermalore occurrences. Associated minerals include sylvanite, hessite, altaite, petzite, empressite, native tellurium, native gold, galena, sphalerite, colusite, tennantite and pyrite.[2]

References