CRYSTALLINE COMPOSITION OF EQUINE URINARY SABULOUS DEPOSITS

The composition and crystal morphology of 141 equine sabulous deposits were determined by infrared spectroscopy (IR), scanning electron micr oscopy (SEM) and energy dispersive X-ray analysis (EDX). The IR analys is revealed that all investigated deposits contained calcium carbonate s (calcite, CaCO3, and/or vaterite, CaCO3) as major constituents; 42 s amples were composed of calcite and vaterite, 33 of calcite, 18 of cal cite/vaterite and calcium oxalate, and 17 of vaterite. The remaining s pecimens contained calcite/vaterite and other compounds (calcium phosp hates, sulphate and/or oxalates and/or silica). The examination of 44 selected samples by means of SEM/EDX, revealed the characteristic morp hology and elemental composition of the constituents of the sabulous d eposits. Calcite crystals showed a typical spherical shape, as well as other less common rhombohedral habit. Vaterite displayed a ''flower'' or ''star'' appearance and also a ''mulberry'' shape. Less frequent w as a spherular habit for vaterite resembling that of calcite. Elementa l analysis of both calcite and vaterite crystals showed, besides calci um, varying proportions of magnesium and potassium. It is concluded th at calcite and vaterite were mainly present in a substituted form. Cal cium oxalate dihydrate crystals showed their characteristic bipyramida l morphology. Calcium oxalate monohydrate crystals, which were less fr equent, exhibited ''dumbbell'' or ''hour-glass'' shape.