Krennerite Locality: Cresson Mine, Eclipse Gulch, Cripple Creek District, Teller County , Colorado , USA ( Locality at mindat.org ) Size: 3.0 x 2.7 x 2.5 cm. This rare gold silver telluride forms in some of the finest crystals in the world in the Cripple Creek Mining District. Fine crystals of Krennerite on matrix are virtually impossible to obtain anymore as the mines around Cripple Creek have long been defunct. This specimen features a few sharp, lustrous, platy, silvery colored crystals of Krennerite on Quartz matrix. These specimens are virtually impossible to obtain on the market these days. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Krennerite
An orthorhombic gold telluride in which silver can replace up to a quarter of the gold.
Intro adapted from Wikipedia (CC BY-SA).
Krennerite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Au₃AgTe₈.
It crystallizes in the orthorhombic crystal system (space group Pma2).
Key properties: Mohs hardness 2–3; specific gravity 8.62; pale yellow streak; Very high metallic luster.
IMA symbol Knn, grandfathered status — known before the IMA’s founding, named in 1877.
Found in hydrothermal veins with other tellurides.
It is found associated with Calaverite, coloradoite, sylvanite, krennerite, petzite, hessite, tellurium, gold, pyrite, quartz.
The name refers to József A. Krenner (1839–1920), Hungarian mineralogist who first noted the species.