Kidney stones or renal calculi are solid concretions or crystal aggregations formed in the kidney from dissolved urinary minerals. There are many types of kidney stones based on the crystals they are made up of. The most common calculi are made up of calcium oxalate (mulberry calculus). The second common calculi are made up of calcium phosphate (staghorn calculus). It is called so because of its shape. It takes the shape of the renal calyces and the pelvis. Rarely, struvite stones are produced by urea-splitting bacteria in people with urinary tract infections. Patients with certain metabolic abnormalities may produce uric acid stones (smooth and round calculus) or cystine stones. The condition of having calculi in the urinary tract is Urolithiasis. The condition of having calculi in the Kidney is Nephrolithiasis. Kidney stones cause severe pain in the abdomen & haematuria (blood in urine). Kidney stones can be treated by Lithotripsy (use of sound waves to break the stone) or surgery