Black Pigment Gallstones : Composition

Comments:
Black Pigment Gallstones - Chemical Composition: They are composed of oxidized polymer-like complexes of calcium bilirubinate, calcium phosphate and calcium carbonate embedded in a glycoprotein matrix. They have little to no cholesterol. Approximately 50% to 75% of black stones are radiopaque due to calcium carbonate and calcium phosphate content and readily visualized on plain radiographs.

The image shows black pigment stones. The dark greenish-black color is due to high content of calcium bilirubinate.