The mineral uytenbogaardtite, Ag3AuS2, is a soft, greyish white sulfide 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 (Ag3AuTe2) and fischesserite (Ag3AuSe2) the uytenbogaardtite group. The type locality, Bengkulu.
It is named after the Dutch mineralogist Willem Uytenbogaardt (1918–2012), Professor of Geology, Technical University, Delft , The Netherlands, prominent ore microscopist.