The remaining twenty percent is composed of pigment stones. Pigment stones are small, dark stones that are composed of calcium salts that can be found in bile. Both cholesterol stones and pigment stones make up . There is alot of risks that are apparent with pigment stones such as cirrhosis, biliary tract infections, and hereditary blood cell disorders, such as sickle cell anemia. Although there is the two distinct stones above, it isn't unusual for stones to exist that are mixed in origin. Gallstones aren't limited to one particular section - they can occur anywhere within the bilary tree. The bilary tree includes the gallbladder and the common bile duct. Gallstones vary greatly in size and numbers. It is possible for the gallbladder to develop one single stone that is as big as golfball, or for it to create several thousand which can be as small as a grain of sand.