Epitaxial considerations in urinary stone formation. I. The urate-oxalate-phosphate system.

We examined the epitaxial relationships and the growth kinetics of hydroxyapatite and calcium oxalate monohydrate on uric acid and sodium urate at sustained supersaturations of hydroxyapatite and calcium oxalate monohydrate, respectively. These phases can grow even at very low supersaturations on both uric acid and sodium urate seed crystals. Our findings agree with theoretical predictions for epitaxial growth. The crystallization kinetics of both hydroxyapatite and calcium oxalate monohydrate are identical with those for the growth of seed crystals of these phases in pure supersaturated solutions.