Wiktionary
uytenbogaardtite
n. (context mineralogy English) A tetragonal-trapezohedral gray white mineral containing gold, silver, and sulfur.
Wikipedia
Uytenbogaardtite
The mineral uytenbogaardtite, AgAuS, is a soft, greyish white sulfide mineral, occurring in hydrothermal Au-Ag-quartz veins. It occurs as tiny crystals, visible only with a microscope. It has a metallic luster and a hardness on the Mohs scale of 2 ( gypsum).
It forms, together with petzite (AgAuTe) and fischesserite (AgAuSe) the uytenbogaardtite group. The type locality is Tambang Sawah, Bengkulu district, Sumatra island, Indonesia.
It is named after the Dutch mineralogist Willem Uytenbogaardt (1918–2012), Professor of Geology, Technical University, Delft, The Netherlands, prominent ore microscopist.