In ceramics, enamels, and glass AU is used to create Reds, rose,
pink and purple.
Luster’s (dissolved metals in resinous base) leave a microns thick
metal coating, which looks obviously metallic, or if very thin
Many recipes will make yellow enamel/glazes: Red iron oxide with
rutile, manganese with salts of Zirconium, others used in various
proportions-Vanadium, cadmium, nickel, lead and of course most
famous but no longer legal- uranium (yellow cake).
I am an avid potter who likes to make my own glazes. (OK OK so my
sister taught me!) best regards, Cecelia