Scanning Microscopy


The composition and crystal morphology of 141 equine sabulous deposits were determined by infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The IR analysis revealed that all investigated deposits contained calcium carbonates (calcite, CaCO3, and/or vaterite, CaCO3) as major constituents; 42 samples were composed of calcite and vaterite, 33 of calcite, 18 of calcite/vaterite and calcium oxalate, and 17 of vaterite. The remaining specimens contained calcite/vaterite and other compounds (calcium phosphates, sulphate and/or oxalates and/or silica). The examination of 44 selected samples by means of SEM/EDX, revealed the characteristic morphology and elemental composition of the constituents of the sabulous deposits. 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 was a spherular habit for vaterite resembling that of calcite. Elemental analysis of both calcite and vaterite crystals showed, besides calcium, varying proportions of magnesium and potassium. It is concluded that calcite and vaterite were mainly present in a substituted form. Calcium oxalate dihydrate crystals showed their characteristic bi pyramidal morphology. Calcium oxalate monohydrate crystals, which were less frequent, exhibited "dumbbell" or "hour-glass" shape.

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