Fluorite (also called fluorspar) is the crystal form of the inorganic compound calcium fluoride. The term "fluorescence," a type of luminescence by a substance that has absorbed light or radiation, is derived from this…

Barium (atomic symbol Ba) is an alkaline Earth metal. Barite (also spelled baryte) is a mineral composed of barium sulfate. It is used in paints, inks, paper, and rubber. It is also used in radiology for diagnostic…