Minerals in biological systems are deposited in an organic and matrix and assemble into calcareous structures or skeletons. The organic matrix consists of soluble and insoluble components containing lipids, carbohydrates and glycoproteins. The matrix is important in calcification, and in crystal formation and regulation. Invertebrates are good systems to study calcification. This project uses an octocoral, a colonial cnidaria commonly known as a sea whip, which forms microscopic spicules of calcium carbonate crystals associated with a matrix. The colonies are large enough to provide a sufficient amount of organic matrix for biochemical analysis and isolation of antigens for antibody preparation. This organism is an excellent system to probe the mechanisms of biomineralization.