Pure fluorite is transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental andlapidaryuses. Industrially, fluorite is used as afluxfor smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride forhydrofluoric acidmanufacture, which is the intermediate source of most fluorine-containingfine chemicals. Optically clear transparent fluorite lenses have lowdispersion, so lenses made from it exhibit lesschromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet and mid-infrared ranges, where conventional glasses are too absorbent for use.