The epitaxially induced crystal growth of calcium oxalate by crystalline uric acid.

Seed crystals of anhydrous uric acid were shown to epitaxially induce the crystal growth of calcium oxalate monohydrate from its metastable supersaturated solution. Scanning electron microscopic examination of crystalline material isolated from the kinetic experiments supports the chemical evidence that calcium oxalate had been nucleated by uric acid. In spite of close lattice similarities between some of the faces of the two phases, the induction period required for heterogeneous nucleation by the seed material was about half of that required for precipitation in the absence of potential nucleating agents. This has created some doubt as to whether crystalline uric acid has an influence on the formation of calcium oxalate lithiasis.