Stones can cause disease by several mechanisms: * Irritation of nearby tissues, causing pain, swelling, and inflammation * Obstruction of an opening or duct, interfering with normal flow and disrupting the function of the organ in question * Predisposition to infection (often due to disruption of normal flow) A number of important medical conditions are caused by stones: * Nephrolithiasis (kidney stones) * Can cause hydronephrosis (swollen kidneys) and kidney failure * Can predispose to pyelonephritis (kidney infections) * Can progress to urolithiasis * Urolithiasis (urinary bladder stones) * Can progress to bladder outlet obstruction * Cholelithiasis (gallstones) * Can predispose to cholecystitis (gall bladder infections) and ascending cholangitis (biliary tree infection) * Can progress to choledocholithiasis (gallstones in the bile duct) and gallstone pancreatitis (inflammation of the pancreas) * Gastric calculi can cause colic, obstruction, torsion, and necrosis.
Calculus 
Ossification
Enema
Cholesterol crystal
Granulation tissue
Neoplasm
Fibrocartilage callus
Granulation