Fluorite
The most colorful mineral on Earth, fluorescing under UV. England's Blue John Cavern (Derbyshire) has been carved since Roman times; Illinois' Cave-in-Rock fluorite was long America's state mineral source; China now leads production.
Known origins & mines
Blue John Cavern Castleton · United Kingdom
Blue John — banded purple-yellow fluorite mined under Treak Cliff since Romans; only ~500 kg remains yearly, carved into Ashford-in-the-Wate…
Xianghualing Hunan Mines · China
Hunan tin mines grow museum-grade octahedral fluorite in candy colors — Chinese specimen dealers dominate world fluorite supply today.…
Cave-in-Rock Fluorite District · United States
Illinois state mineral source — Cave-in-Rock purple-and-yellow fluorite with phantom zoning fed American industry until 1995 closure.…
Okorusu Fluorspar Mine · Namibia
Fluorspar mine near Otjiwarongo celebrated worldwide for intense green octahedral fluorite on quartz - a staple of top collections since the…
Rogerley Fluorite Mine · United Kingdom
English mine famous among collectors for green daylight/fluorescent purple fluorite twins — closed 2019 but specimens remain benchmarks.…