Crystaloptical and spectroscopical findings with calcium oxalate crystals in the urine sediment: a contribution to the genesis of oxalate stones

Transmitted light microscope and scanning electron microscope investigations reveal various shapes of urine calcium oxalate crystals. In addition to tetragonal bipyramids, weddellite forms further crystal shapes that have been heretofore interpreted exclusively as whewellite crystals. Weddellite is stabilized by urine foreign ions. In vivo formation of whewellite crystals occurs with massive crystallization only.