What is Fluorite? That fluorite has an unusual dispersion characteristic not found in optical glass, which can be used to remove chromatic aberration and was discovered by Abbe (1840-1905). At the time, natural fluorspar crystals were used, so applications were limited to small diameter lenses of microscopes. The possibilities of fluorite were noted early at Canon, and research aimed at making artificial crystals resulted in successful commercial lenses. Optron, a Canon affiliate, is one of the few companies that mass-produce fluorite. Fluorite is used in the focusing groups of zoom lenses to correct chromatic aberration on the telephoto side. It is particularly effective in correcting secondary spectrum aberrations.