There are six main components of stones, which, in order of percentage, are oxalate, phosphate, urate, carbonate, cystine, and xanthine stones. Most stones are a mixture of two or more components. Because crystals often account for more than 60% of the weight of the stone, so the clinical crystal composition to name. (1) Calcium oxalate stones account for 80% to 84% of the stones, often yellow-brown or copper-colored, smooth surface (calcium oxalate monohydrate), rough (calcium oxalate bicarbonate), often mulberry-like, brown. Male onset is common, most often with a family history, and is clearly visible on x-ray. Calcium oxalate crystals are often present within the urine sediment. (2) Calcium phosphate stones: accounting for 6% to 9% of the stones, the stones are white, rough surface, often antler-like, hard texture. Often formed in alkaline urine. They are more common in young adult males, mostly with family history, and are clearly visible on x-ray. (3) Uric acid (urate) stones: 6%-10% of the stones, smooth surface, often antler-shaped, yellow or brown color, hard texture, fuzzy or can not appear on the x-ray film. They are more common in males, especially in patients with gout, and usually have a family history. Uric acid crystals are seen within the urine sediment. (4) magnesium ammonium phosphate stones: accounting for 6%-9% of the stones, the stones are yellow or dirty gray, dendritic or antler-like, soft texture. To women for the most common, more patients with urinary tract infections, can not be through the x-ray. Ammonium magnesium phosphate crystals can be seen in the urine sediment. (5) cystine stones: accounting for less than 2% of the stones, stones yellow or white, smooth surface, waxy appearance, round, not easy to pass through the x-ray, often formed in acidic urine. Cystine crystals can be seen in the urine sediment. (6) xanthine stones: these stones are rarely seen, white or yellow-brown color, texture is very brittle, can not pass through the x-ray, usually formed in acidic urine. However, the current drug lithotripsy is mainly applicable to uric acid stones and cystine stones. Physical properties of common uroliths Name of urolith Shape Surface Color Hardness X-ray visualization Calcium oxalate Round or ovoid Rough Dark brown Hard (+ + + +) Phosphate Indeterminate or staghorn-shaped Granular Slightly yellowish Hard (+ + + +) Carbonate Massive Smooth or slightly rough Grayish Brittle (+ + + +) Urate Round or ovoid Smooth or rough Yellowish to brownish Firm (±) Cystine Indeterminate Smooth Pale yellow Brittle (±) Xanthine Round or ovoid Smooth Brownish Yellow Firm (±) Cystine Indeterminate Smooth Light yellow Brittle (±) Xanthine Round or ovoid Smooth Brownish yellow Firm (±)