Fluorite, also called fluor, fluorspar is a mineral often fluorescent in ultraviolet light. Massive fluorite may resemble calcite, but it is heavier and does not effervesce when treated with hydrochloric acid. It is distinguished from gypsum and quartz by its hardness. Fluorite deposits form under a wide variety of conditions: as veins produced by hydrothermal alteration, as beds and cavities in sedimentary rocks, in hot spring deposits, and in pegmatites.
