Commonest type of gall stone is
Most common gall stones are Mixed gall stones and account for 90% of calculi Mixed stones Mixed (brown pigment stones) typically contain 20-80% cholesterol (or 30-70%, according to the Japanese- classification system). Other common constituents are calcium carbonate, palmitate phosphate, bilirubin and other bile pigments (calcium bilirubinate, calcium palmitate and calcium stearate). Because of their calcium content, they are often radiographically visible. They typically arise secondary to infection of the biliary tract which results in the release of b-glucuronidase (by injured hepatocytes and bacteria) which hydrolyzes bilirubin glucuronides and increases the amount of unconjugated bilirubin in bile. Between 4% and 20% of stones are mixed. Gallstones can vary in size and shape from as small as a grain of sand to as large as a golf ball.The gallbladder may contain a single large stone or many smaller ones. Pseudoliths, sometimes referred to as sludge, are thick secretions that may be present within the gallbladder, either alone or in conjunction with fully formed gallstones. Ref: Bailey and love 27th edition Pgno : 1198
Cholesterol stone
Pigment
Mixed
All are equally common
G.I.T