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What are kidney stones made of?

Most kidney stones in Australia are Calcium stones, either Calcium Oxalate or Calcium Phosphate. Calcium stones account for over 90% of stones and are usually idiopathic – not caused by a specific disease process. Calcium stones are hard (like a rock) and cannot be dissolved. The composition of kidney stones generally does NOT relate to dietary intake.

Composition of Kidney Stones

  • Calcium Stones
    • Calcium Oxalate
    • Calcium Phosphate
    • Mixed Calcium Oxalate / Calcium Phosphate
  • Uric Acid Stones – usually a genetic predisposition
  • Struvite Stones – from recurrent Urinary Tract Infections
  • Cystine Stones – rarely seen, associated with a genetic disease
  • Xanthine Stones – very rare
  • Stones caused by medicines (very rare) e.g. indinavir, sulfadiazine and triamterene.