The qualitative analysis of renal calculi with the polarising microscope.

The crystallographic method of Prien and Frondel for the qualitative analysis of renal calculi has been employed for seventeen years. The method was supplemented by occasional chemical tests. Advantages of the crystallographic method over other procedures are the ability to identify specific minerals even in trace amounts, the capability to analyse very small stones, and the rapidity with which analyses can be performed. Data are presented for 1653 calculi.