After the stone has been expelled, it should definitely be examined for its composition, as this is the only way to ensure safe and effective therapy and prophylaxis.
Stone analysis is performed using physical methods such as infrared spectroscopy and X-ray diffraction analysis. These detect the composition of the respective stone on the basis of the absorption spectra of infrared rays or the various diffraction spectra of X-rays.
The following parameters can be distinguished for the different types of stone:
| Stone type | Chemical components | X-ray density* |
| Calcium oxalate (approx. 30 %) | Calcium oxalate monohydrate (Whewellite stone) | Positive |
| Calcium oxalate dihydrate (weddellite stone) | Positive | |
| Uric acid (5-10%) | Uric acid | Negative |
| Uric acid dihydrate | Negative | |
| Calcium phosphate (1%) | Calcium phosphate or mixed stone with calcium oxalate or struvite (brushite stone)Carbonatapatite | Positive |
| Struvite | Magnesium ammonium phosphate | Positive |
| Mg ammonium hydrogenurate (10-20%). | Salt of uric acid and ammonium ions. | Negative |
| Cystine (2-3%) | Cystine | Weak positive |
| Xanthine | Xanthine | Negative |
| Dihydroxyadenine | Dihydroxyadenine | Negative |
* Radiographic density indicates whether or not a stone is visible on an X-ray examination.
