Cuttlefish Bone Cuttlefish bone refers to the internal cartilaginous shell of the cuttlefish, a relative of the squid and octopus. Cuttlefish bone is typically smooth and white, with small, wavy lines or ridges. The shell is rich in minerals such as calcium and carbon, and contains more than a dozen amino acids. It is usually boiled, then dried and prepared as a powder for herbal remedies. A cuttlebone is not actually a bone, but rather the internal shell of the Cuttlefish, a small, squid-like cephalopod. In the Cuttlefish, the cuttlebone is filled with gasses and helps control the fish's buoyancy in the water. While for years people have harvested and used cuttlebones for various purposes, the most widely recognized use of the cuttlebone is as a supplement and exercise toy for birds.