Tag: Hydrothermal
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Weddellite and Whewellite
Weddellite (CaC2O4·2H2O) is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica. Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite’s short tetragonal dipyramids. It was first described in 1936 but only named in 1942. Structural properties Weddellite, or calcium oxalate dihydrate, crystallises in a tetragonal system: the classic crystal…
