Megawite
Megawite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula CaSnO₃.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Perovskite structural group.
Key properties: specific gravity 5.06; White streak; Vitreous luster; optically biaxial.
IMA symbol Mgw, IMA status: approved, named in 2009.
Occurs as minute inclusions in rock-forming minerals in altered ignimbrite xenoliths in a caldera. Probably formed by contact metamorphism at low pressure and >800ºC.
It is found associated with Spurrite, reinhardbraunsite, rondorfite, wadalite, srebrodolskite, lakargiite, perovskite, kerimasite, elbrusite-(Zr), periclase, hydroxylellestadite.
The mineral was named to honor British crystallographer Helen Dick Megaw (1907-2002) for significant contributions to our understanding of the perovskites.