The inorganic part of
shark teeth consisted of fluoroapatite with a fluoride content in the enameloid of 3.1 wt.%, i.e., close to the
fluoride content of the geological fluoroapatite single crystal (3.64 wt.%). Scanning electron micrographs
showed that the crystals in enameloid were highly ordered with a special topological orientation (perpendicular
towards the outside surface and parallel towards the center).