Clinical Biochemistry Unit, Canterbury Health Laboratories, Christchurch, New Zealand. chris.sies@cdhb.govt.nz
Quartz stones are often considered to be of non-human origin or factitious, although in some cases, they may have a biological aetiology. X-ray diffraction (XRD) spectroscopy was used to analyse fragmented renal stones from a 61-year-old lady who presented with bilateral nephrocalcinosis. Analysis of the calculi from the left kidney showed a mixed composition: 50% calcium oxalate monohydrate and 50% quartz. This case highlights the usefulness of XRD in the differentiation of authentic from possibly factitious renal calculi.