whewellite

Together, whewellite and weddellite are the most common renal calculi.

Whewellite is used as a thermogravimetric analysis standard due to its well known decomposition temperatures and products.

Whewellite, or at least crystalline calcium oxalate, does also arise from biological sources.

It occurs with whewellite, urea, phosphammite and aphthitalite.

The cocoons contain minute crystals of whewellite, produced by the larva's Malphigian tubule system.

Calcium oxalate monohydrate (whewellite)

Inocybe, cystidium, hydathode, calcium oxalate, whewellite.

Whewellite is a mineral, hydrated calcium oxalate, formula CaCO HO.

A detailed crystallographic study showed that these twin crystals undoubtedly belong to the monoclinic system, i.e., the monohydrated form of the calcium oxalate or whewellite.

For example, whewellite, CaCO HO is an oxalate that can be deposited in hydrothermal ore veins.

Some oxalates can be found in nature and the most known naturally occurring oxalates are whewellite and weddellite, which are calcium oxalates.

Hydrated forms of the compound occur naturally as three mineral species: whewellite (monohydrate, known from some coal beds), weddellite (dihydrate) and a very rare trihydrate called caoxite.

Occasionally, weddellite partially dehydrates to whewellite, forming excellent pseudomorphs of grainy whewellite after weddellite's short tetragonal dipyramids.

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.

Energy-dispersive X-ray microanalyses confirmed that all crystal types were rich in calcium, and X-ray diffraction identified both the dihydrate (weddellite) and monohydrate (whewellite) forms of calcium oxalate.

Our observations provide the first strong evidence of cuticular hardening by mineralization in the Arachnida, and the only known instance of the use of whewellite as a general intracuticular hardening agent in arthropods.

Two types naturally occur, calcium oxalate monohydrate, or whewellite (CaCO HO), and calcium oxalate dihydrate, or weddellite (CaCO 2HO).

Calcite (calcium carbonate) is the mineral deposited by mites representating the Ptyctima, but three species of Enarthronota (Eniochthonius minutissimus, Archoplophora rostralis, and Prototritia major) deposit whewellite, a form of calcium oxalate.

Crystals were isolated from leaves, purified, verified for shape with scanning electron microscopy, and characterized as calcium monohydrate (whewellite; Rhynchosia, Phaseolus, and Canavalia) or dihydrate (weddellite; Begonia) by X-ray powder diffraction and infrared spectroscopy.