PLUMBOGUMMITE Pseudomorph After PYROMORPHITE

SPECIMEN DESCRIPTION

A fine large miniature/small cabinet specimen of the now classic pseudomorphs of translucent Plumbogummite coating and partly replacing substantial crystals of canary yellow prismatic Pyromorphite crystals, these measuring to 3.5 cm in an open cluster. This fine specimen is from the Yangshuo mine in Yangshuo County, Guilin Prefecture, within the Guangxi Zhuang Autonomous Region of China. Yangshuo mine works a hydrothermal lead-zinc deposit, hosted in limestone, sandstone and shale of the Devonian Wuzhishan formation which are locally intruded by granite and some lamprophyre dykes. The Plumbogummite forms a smoky, blue to light sage green replacement over the chunky Pyromorphite crystals, showing the initial stage in the process of pseudomorph replacement. This occurs as a piecemeal process whereby each atom is individually replaced, gradually altering the Pyromorphite (lead phosphate chloride) to Plumbogummite (hydrated lead aluminium phosphate).