The polymorphs of calcium carbonate in human gall stones.

Gall stones from 64 patients that had been examined by X-ray diffraction in 1962 were re-examined in 1980 to find out if any phase transition of the calcium carbonate polymorphs had occurred. In the vast majority of cases, exactly the same powdered specimen was re-examined. In a few cases, more material was added or another stone from the same patient was analysed. There was no evidence that a phase transition had occurred upon storage of the specimens in room air, as had earlier been suggested in the literature. The three polymorphs of calcium carbonate, vaterite, aragonite and calcite therefore appear to precipitate in vivo mixed with each other in various proportions and/or with the other constituents of human gall stones. Complete dehydration of cholesterol monohydrate to cholesterol had occurred in all specimens.