A bill designating Fluorite as the Official State mineral was passed in 1965 by the Illinois General Assembly. Fluorite is now also recognized as a gemstone for use in jewelry. Although most Fluorite found in Illinois was yellow or purple, due to impurities, Fluorite can come in almost any color as well as the quite colorful 'rainbow' variety..
Since the early 1800s, fluorite has been mined in southeastern Illinois. The fluorspar-rich region, which reaches from southeastern Illinois into parts of Kentucky, was called the Illinois-Kentucky Fluorspar Mining District. In Illinois, fluorite was mined almost exclusively in Hardin and Pope Counties.
The main production came from fissure-vein deposits in the Rosiclare district, and stratiform (bedding plane) deposits in the Cave in Rock district . Other areas in the two counties yielded smaller amounts of the mineral. Most mining was underground, as much as 1,300 feet deep. But open-pit mines operated where fluorite deposits intersected land surface. Illinois displaced Kentucky as the country's leading producer of fluorite in 1942. For many years, Illinois accounted for more than 50% of total U.S. fluorspar production. But by 1990, more than 90% of the fluorite used in the U.S. was imported. The last fluorspar mine in Illinois closed in December 1995. Fluorspar is no longer mined anywhere in the United States.
The main production came from fissure-vein deposits in the Rosiclare district, and stratiform (bedding plane) deposits in the Cave in Rock district . Other areas in the two counties yielded smaller amounts of the mineral. Most mining was underground, as much as 1,300 feet deep. But open-pit mines operated where fluorite deposits intersected land surface. Illinois displaced Kentucky as the country's leading producer of fluorite in 1942. For many years, Illinois accounted for more than 50% of total U.S. fluorspar production. But by 1990, more than 90% of the fluorite used in the U.S. was imported. The last fluorspar mine in Illinois closed in December 1995. Fluorspar is no longer mined anywhere in the United States..
.
.
.
