Mineral Species: Shannonite

Chemical Formula: Pb2OCO3

Chemical Name: Lead Carbonate Oxide

Mineral Class: Carbonate

Mineral Notes: Shannonite is an extremely rare secondary mineral formed in the oxidation zone, probably by acidic groundwater reacting with Cerussite, in a lead ore deposit at Grand Reef Mine, Arizona, USA. It is named after David Michael Shannon, mineral dealer and collector, Mesa, Arizona, USA, who provided the original material. The mineral was approved by the IMA in 1993 as a new mineral species. 

Description: Clusters of pale-yellow Shannonite crystals on the surface of the supporting matrix. The mineral forms flattened blocky crystals which have a strong lustrous surface. This, combined with the unusual colour, makes this an excellent example of a very rare mineral species.

Location: Tonopah-Belmont Mine, Maricopa Co., Arizona, USA.