These pieces are found in a hydrothermal lead-zinc deposit, hosted in limestone and sandstone, with granite intrusions. Two mines operate in the area and there might be some confusion about the exact mine - the Daoping and Yangshuo mines, connected underground. Plumbogummite is a rare secondary lead phosphate mineral coating bright yellow pyromorphite crystals.
Exceptional color under midwave (MW) UV, duller under SW, with no response LW. This is one of the few fluorescent mineral specimens that is absolutely best under MW.