Polymorph modifications of calcium carbonate in gallstones

The phase and microelement compositions of gallstones collection were studied and correlations were found between them. According to the X-ray powder diffraction analysis, the main constituents of the stones were found to be cholesterol and different polymorphs of calcium carbonate, the latter were detected in 30% of stones. The analysis of the phase composition, paragenesis and abundance of various CaCO3 polymorphs shows that the popularity of one or the other crystalline form of CaCO3 in gallstones is directly opposite to that characteristic of natural systems. Vaterite has been found in 87% of analyzed stones, aragonite is present in 55% of them, and calcite is found in 45% only. Vaterite is present in 34% of gallstones as single CaCO3 polymorph, together with cholesterol. Aragonite is found only in two pigment stones, and calcite is identified in two cholesterol stones. In other stones, two or three modifications are simultaneously present in different quantitative relations, together with cholesterol and/or pigment. “Pure” carbonate stones are very rarely observed. We have seen only one such stone and the internal black zone of another stone composed entirely of three CaCO3 modifications (according to X-ray data). In both samples, the Fe, Zn, Sr and Pb contents are high, and the Mn content is maximal. The obtained results show existence of some correlation between the phase and the microelement composition of the gallstones.