MINERALS-FLOURITE

Fluorite

Fluorite (calcium fluoride, CaF₂), known commercially as ‘fluorspar’, is the principal source of fluorine and fluorine chemicals, including the important industrial chemicals hydrogen fluoride (HF) and hydrofluoric acid (70% HF). A large range of fluorine-containing chemicals (CFCs, HFCs and HCFCs) are used as industrial solvents, refrigerants, aerosol propellants and plastic foams. Synthetic cryolite (Na₃AlF₆) is used as an electrolyte for smelting aluminium metal. Ceramic-grade fluorspar is used in decorative glassware and enamel, and metallurgical-grade fluorspar is used as a fluxing agent in the steel industry.

World production is ~4 Mt/year, but declining use of CFCs and more efficient usage in the steel and aluminium industries is reducing demand. All of Australia’s requirements are imported.

The only commercial production of fluorite in South Australia has been from very small vein deposits in the Olary region. Fluorite was produced for the steel and glassware industries from two deposits within 1 km of Plumbago homestead, 40 km north of Manna Hill. Over 580 t were mined during 1932–36, and 110 t in 1956–58. Veins within metasediments of the Willyama Supergroup are up to 1 m wide and consist of quartz and purple fluorite. At Mutooroo, 40 km south of Cockburn, a swarm of veins containing quartz, purple fluorite, calcite and barite occur within Adelaidean metasediments. The 55 t mined in 1970–71 exhausted this deposit.

Numerous other small occurrences are known in the region. Narrow veins of green and purple banded fluorite occur within granitic breccia near Mount Gee in the Mount Painter area.

 

Banded fluorite with a drusy quartz coating, Mount Gee area.