This fluorite has pale green cubic crystals that fluoresce a vibrant purple under UV light. 

Pure fluorite is transparent, but impurities generally make it a colorful mineral. It can come in all different colors--the most common being purples, greens, blues and colorless.

A physicist in 1852 coined the term fluorescence from fluorite because like this specimen, many samples of fluorite emit this extraordinary electromagnetic radiation as visible light. 

Fluoride, which is a chemical found in toothpaste, is made from and named after fluorite. 

Fluorite
Choir area, Gobi Desert
Mongolia

Size: 4.44 x 2 x .88 inches
Weight: 5.35 oz.