Any of three grades of titanium-dioxide-based pigments used in the production of paints, paper, and many other products requiring a white pigment with a high hiding power and chemical stability. Rutile and anatase grades are more or less pure titanium dioxide, but owing to a difference in crystal structure, they differ slightly in hiding power and chalking quality. Titanium dioxide of pigment quality is manufactured principally by treating finely ground ilmenite or titanium slag with concentrated sulfuric acid. Also used in ceramics and fiberglass, and in making titanium gems.