Whewellite [SEP] named after
the surfaces of some cacti, and kidney stones frequently have the same composition.
Whewellite was named after William Whewell (1794–1866), an English polymath, naturalist and scientist, professor of moral philosophy at Cambridge and inventor of the system of crystallographic indexing.
Heat decomposition.
Whewellite is used as a thermogravimetric analysis standard due to its well-known decomposition temperatures and products.
See also.
- List of minerals named after people
References.
List of minerals (complete)
Weddellite
Weddellite (CaCO·2HO) 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 1942.
Structural properties.
Weddellite, or calcium oxalate dihydrate, crystallises in a tetragonal system: the classic crystal shape is the eight-face bipyramid. Using bright field microscopy, the weddellite crystals are recognised