Epitaxy as a Growth Factor in Urinary Calculi and Gallstones

EPITAXY1 consists of the growth of one crystal, in one or more particular orientations, on a substrate of another, with a near geometrical fit between the respective networks which are in contact. Thus anthraquinone can grow on rocksalt2 and d- or l-camphor on d- or l-quartz3. That there is some influence of the structures themselves (apart from the geometry) has been proved, but it is of surprisingly minor importance3. There is also a dependence of the degree of misfit which can be tolerated on the degree of supersaturation of the solution from which the epitaxial crystals are deposited4.