<prompt> More than 80 of gall stones is composed ofBile pigmentsCholesterolCalcium saltsPhospolipids  <response>: Ans. b CholesterolRef: Sabiston 20th edition Page 1491 Major structure present in Gall stones is Cholesterol. Pigment stones are given the name when Cholesterol is present in amount of 30. Hence most common stone in Gallbladder is Mixed stone 