[Newberyte in old calculi of the urinary system]

In 542 old calculi belonging to the collection complied by Dr. P. Cifuentes Díaz, we have found newberyte in 81 calculi (14.9%). Newberyte appears in the struvite and apatite calculi in the form of small crystals looking like a mosaic. This results from the transformation of the struvite when it loses NH3 and H2O which we have only found in old urinary calculi.