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Back| Type | Ratio (%) | Crystal | Characteristics | Effect of pH on Solubility | X-ray Density (Bone = 1.0) | Mechanical Properties |
|---|---|---|---|---|---|---|
| Calcium Oxalate | 67.2 | Monohydrate Calcium Oxalate | Brown, cast or mulberry-shaped, hard texture | Little effect | 0.50 (Radiopaque) | Brittle |
| Dihydrate Calcium Oxalate | White, with crystalline spiky protrusions, brittle texture | |||||
| Calcium Phosphate | 22.4 | Hydroxyapatite, Carbonate Apatite, Dihydrate Calcium Hydrogen Phosphate, Tricalcium Phosphate | Light gray, hard, may have concentric layers, dihydrate calcium hydrogen phosphate is the hardest | <5.5 increases | 1.0 (Radiopaque) | Brittle |
| Uric Acid | 6.9 | Anhydrous Uric Acid, Dihydrate Uric Acid, Ammonium Urate, Monohydrate Sodium Urate | Easily absorbs urinary pigments, yellow or brick red, smooth, dense structure, medium hardness | >6.8 increases for anhydrous and dihydrate uric acid; decreases for ammonium urate | 0.05 (Radiolucent) | Brittle |
| Struvite | 1.7 | Hexahydrate Ammonium Magnesium Phosphate | Gray, irregular or staghorn-shaped, loose and fragile | <5.5 increases | 0.20 (Semi-radiolucent) | Brittle |
| Cystine | 1.1 | Cystine | Wax yellow, shiny surface, can be round or staghorn-shaped | >7.5 increases | 0.15 (Semi-radiolucent) | Tough |
Explanation
Calcium-containing stones (calcium oxalate, calcium phosphate) are the most common, accounting for nearly 90% of all stones; uric acid stones mostly occur in male patients; struvite stones are mostly seen in female patients; cystine stones are more common in children. Other types of stones, such as calcium carbonate stones and silicon dioxide stones, are rare.
