Chemical and crystallographic studies on 33 cases of calcium carbonate gallstone (so-called limy bile).

Chemical analyses by atomic absorption spectrophotometry and crystallographic studies by the X-ray powder diffraction method and infrared spectrometry (KBr-disk method) were made on 33 cases of calcium carbonate gallstone or so-called limy bile. Chemically, calcium carbonate was the major constituent, ranged from 33.7 to 91.6% and averaged 77.8%. Crystallographically, calcium carbonate has three different polymorphic crystalline forms; calcite, aragonite and vaterite. In nature the most stable calcite (hexagonal) is most commonly found and aragonite (rhombic) is next. On the other hand vaterite, which is unstable hexagonal modification, rarely occurs in biological systems. But in our gallstone series in man, aragonite was most commonly found, with an occurrence rate of 90.6%, while that of calcite was 62.5%. Even vaterite was found in 28.1%. Moreover three cases contained all three forms of calcium carbonate polymorphs; calcite, aragonite and vaterite. This was a very unusual condition. Some environmental factors controlling the growth of these crystals, such as specificity of the bile, are suggested.