Mechanism of Calcium Oxalate Monohydrate Kidney Stones Formation: Layered Spherulitic Growth

The morphology of calcium oxalate monohydrate (COM) kidney stones is studied using polarized light microscopy and X-ray diffraction. We show that polycrystalline structure of COM stones exhibits spherulitic texture where the arrangement of crystallites indicates that their fast growth direction is perpendicular to the corresponding radius of spherulite, resulting in the layered morphology. This is in contrast to “normal” spherulites, where the crystal growth process leads to the formation of a radiating array of fiber crystallites. We demonstrate that COM stones consist of spherulitic domains. The domains have the shape of comparatively narrow randomly distorted cones in which the crystallites form strong texture, so that their crystallographic axes have almost the same directions and the [100] crystallographic planes are nearly perpendicular to the radial direction of the domain. However, the order among the domains does not exist. Deviations of their radial directions from the corresponding radial direc...