Optic Crystal Votive. Each is created by hand. Optical crystal (or optic crystal) is short for ophthalmic crystal, which refers to lenses. As such, it is not only used to create gorgeous optic crystal votives, but in the Hubble Telescope! During the manufacturing process, optical crystal is heated to a very high temperature and then allowed to cool very slowly, a process that eliminates bubbles and imperfections. The result is a very hard material that is much clearer than glass or leaded crystal -- and more valuable.