What does the crystallography of stones tell us about their formation?

The mineral phase makes up most of the mass of a kidney stone. Minerals all come in the form of crystals that are regular arrangements of atoms or molecular groupings at the atomic scale, bounded macroscopically by well-defined crystal faces. Pathologic nephroliths are a polycrystalline aggregate of submicron crystals. Organic macromolecules clearly have an important role in either promoting or preventing aggregation and in altering the morphology of individual submicron crystals by influencing the surface energies of different faces. Crystals, similar in morphology to those grown in solution, are often found for calcium oxalate dihydrate, brushite, cystine and struvite. This is not the case for calcium oxalate monohydrate and hydroxyapatite, two of the most common constituents of stones.