Greenish yellow microcrystals of the very rare uranium mineral sharpite from a little known locality in France (Le Brugeaud Mine, Bessines-sur-Gartempe, Haute-Vienne, Nouvelle-Aquitaine, France). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Sharpite
Sharpite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Ca(UO₂)₃(CO₃)₄·3H₂O.
It crystallizes in the orthorhombic crystal system.
Key properties: Mohs hardness 2.5–3; specific gravity 4.45; optically biaxial.
IMA symbol Shp, grandfathered status — known before the IMA’s founding, named in 1938.
A very rare secondary mineral formed in the oxide zone of hydrothermal uranium deposits.
It is found associated with Uranophane, becquerelite, schoepite, curite, masuyite, vandenbrandeite, ianthinite, uraninite.
The mineral was named to honor Major Robert Richard Sharp (1881–1956), English engineer and prospector who discovered the Shinkolobwe deposit, Congo.