[6] Pure fluorite is colourless and transparent, both in visible and ultraviolet light, but impurities usually make it a colorful mineral and the stone has ornamental and lapidary uses.

Optically clear transparent fluorite has anomalous partial dispersion, that is, its refractive index varies with the wavelength of light in a manner that differs from that of commonly used glasses, so fluorite is useful in making apochromatic lenses, and particularly valuable in photographic optics.

[7][8] Agricola, a German scientist with expertise in philology, mining, and metallurgy, named fluorspar as a Neo-Latinization of the German Flussspat from Fluss (stream, river) and Spat (meaning a nonmetallic mineral akin to gypsum, spærstān, spear stone, referring to its crystalline projections).

In archeology, gemmology, classical studies, and Egyptology, the Latin terms murrina and myrrhina refer to fluorite.

[11] In book 37 of his Naturalis Historia, Pliny the Elder describes it as a precious stone with purple and white mottling, and noted that the Romans prized objects carved from it.

[16][needs update] One of the largest deposits of fluorspar in North America is located on the Burin Peninsula, Newfoundland, Canada.

He noted an occurrence of "galena" or lead ore and fluoride of lime on the west side of St. Lawrence harbour.

[17][18][19] In 2018, Canada Fluorspar Inc. commenced mine production again[20] in St. Lawrence; in spring 2019, the company was planned to develop a new shipping port on the west side of Burin Peninsula as a more affordable means of moving their product to markets,[21] and they successfully sent the first shipload of ore from the new port on July 31, 2021.

[23] The largest documented single crystal of fluorite was a cube 2.12 meters in size and weighing approximately 16 tonnes.

In the Emilio mine, in Loroñe, Colunga, the fluorite crystals, cubes with small modifications of other figures, are colourless and transparent.

In the Moscona mine, in Villabona, the fluorite crystals, cubic without modifications of other shapes, are yellow, up to 3 cm of edge.

The mineral Blue John is now scarce, and only a few hundred kilograms are mined each year for ornamental and lapidary use.

[26] Recently discovered deposits in China have produced fluorite with coloring and banding similar to the classic Blue John stone.

In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green, and white also occur.

The fluorescence of fluorite may be due to mineral impurities, such as yttrium and ytterbium, or organic matter, such as volatile hydrocarbons in the crystal lattice.

Fluorite is a major source of hydrogen fluoride, a commodity chemical used to produce a wide range of materials.

In the early years of the 21st century, the stepper market for calcium fluoride collapsed, and many large manufacturing facilities have been closed.

Canon and other manufacturers have used synthetically grown crystals of calcium fluoride components in lenses to aid apochromatic design, and to reduce light dispersion.

As an infrared optical material, calcium fluoride is widely available and was sometimes known by the Eastman Kodak trademarked name "Irtran-3", although this designation is obsolete.

By using combinations of different types of glass, lens manufacturers are able to cancel out or significantly reduce unwanted characteristics; chromatic aberration being the most important.

[36] The refractive qualities of fluorite and of certain flint elements provide a lower and more uniform dispersion across the spectrum of visible light, thereby keeping colors focused more closely together.

With the advent of synthetically grown fluorite crystals in the 1950s - 60s, it could be used instead of glass in some high-performance optical telescope and camera lens elements.

Fluorite and various combinations of fluoride compounds can be made into synthetic crystals which have applications in lasers and special optics for UV and infrared.

[39] Exposure tools for the semiconductor industry make use of fluorite optical elements for ultraviolet light at wavelengths of about 157 nanometers.

Fluorite objective lenses are manufactured by the larger microscope firms (Nikon, Olympus, Carl Zeiss and Leica).

Nikon has previously manufactured at least one fluorite and synthetic quartz element camera lens (105 mm f/4.5 UV) for the production of ultraviolet images.