CaF2 – fluorite powder – is a free-flowing mass obtained by crushing fluorite. Fluorite (fluorspar) is the mineral form of calcium fluoride, CaF2. Fluorite is fragile. Pure fluorite crystals are rare and are highly transparent in both visible and ultraviolet light. However, impurities and defects in its crystal structure usually make it a colorful mineral: it can be yellow, green, blue, blue, reddish-pink, violet, and sometimes violet-black. Fluorite is a typical fluorescent mineral; when heated and after irradiation with ultraviolet light, it glows in the dark. Fluorite is used to produce hydrofluoric acid, and has found applications in atomic, electronic, and space technology. It is also used in various industries, such as those related to glass, aluminum, chemical and metallurgy, and optics.