Fluorite from the Rogerley Mine, England
Contributed by: Michael Crawford
Date: Jul 10th, 2025
Locality: Rogerley Mine, Rogerley Quarry, Stanhope, County Durham, England, UK (See on Mindat)
Size: 9 x 12.5 cm
Description:
A cluster of green fluorite (CaF2) crystals from the Rat Hole Pocket, Rogerley Mine, County Durham, England. This specimen displays the common fluorescent characteristics of Rogerley fluorite. It has very bright blue fluorescence under longwave UV illumination. It also shows blue daylight fluorescence under sunlight. The blue fluorescence dims slightly under midwave and shortwave UV illumination.
The emission spectra show a peak with a maximum at 421 nm. This fluorescence is activated by europium (Eu3+) replacing calcium in the fluorite structure. The fluorite also fluoresces in the ultraviolet region under shortwave illumination. The ultraviolet emission spectrum has two sharp peaks at 319 nm and 341 nm. This ultraviolet emission is activated by cerium (Ce3+) replacing calcium. Another rare earth element (REE), samarium (Sm3+), may be responsible for the green color in this fluorite.
Summary of luminescence responses:
Fluorite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Blue
- Fluorescence under Shortwave (255nm LED) UV light: Blue