A classification of urinary calculi with respect to their composition and micromorphology.

Texture and micro-morphology of 1615 urinary calculi has been studied using scanning electron microscopy and X-ray micro analysis. Together with the results of X-ray diffractometry concerning their phase composition, a classification into five stone classes, 13 stone groups and 17 sub-groups could be evaluated. Especially the large and inhomogeneous class of the calcium-stones could be resolved into 13 stone types. Using this classification, the stone type is characterized by a three digit number containing the stone class, the stone group and in some cases the sub-group. Criteria for classification are typical texture patterns, the occurrence of special crystalline phases or both. These items are presented and clinical relationships discussed.