calculi

See Calculus.

Stones formed in tissues such as the gall bladder (biliary calculus or gallstone), kidney (renal calculus), or ureters. Renal calculi may consist of uric acid and its salts (especially in gout) or of oxalic acid salts. Oxalate calculi may be of metabolic or dietary origin and people at metabolic risk of forming oxalate renal calculi are advised to avoid dietary sources of oxalic acid and its precursors. Rarely, renal calculi may consist of the amino acid cystine.