Unusual Fluorite and Quartz from Qinglong Mine, China
Contributed by: Michael Crawford
Date: Aug 4th, 2025
Locality: Qinglong Mine (Dachang Mine), Dachang Sb ore field, Qinglong County, Qianxinan, Guizhou, China (See on Mindat)
Size: 8 x 17 cm
Description:
Fluorite cubes on a quartz matrix from the Qinglong Mine, Qinglong County, Qianxinian, Guizhou, China. The fluorite cubes are pale purple with dark purple edges and corners. The fluorite is called purple edge fluorite. The fluorite fluoresces blue under all UV wavelengths. It is brightest under longwave light.
The longwave emission spectrum that is commonly seen in fluorite when europium replaces calcium. The spectrum peaks at 421 nm. The shortwave spectrum has a prominent peak with a maximum in the ultraviolet region at 336 nm. There is still a much smaller peak at 421 nm due to europium. The 336 nm peak is likely activated by a rare earth element, but there are no references for the activator’s identity. Cerium activates fluorite emission peaks at 319 nm and 341 nm and yttrium activates fluorite emission peaks at 299 nm and 311 nm.
The orange-red fluorescent mineral appears to be quartz. Red fluorescence in quartz is very rare. This quartz fluoresces weak orange red under midwave and shortwave UV light. Images in mindat.org of similar purple edge fluorite specimens from the Qinglong Mine, the descriptions are fluorite on a matrix of quartz clusters like this specimen. Close up images of the quartz clusters show terminations typical of quartz. The quartz is non-reactive to acid, and it cannot be scratched with a knife point.
The quartz emission spectrum is very noisy because the intensity is weak. Both the midwave and shortwave spectra have peaks around 570 nm, 605 nm, and 685 nm. This pattern does not match any reference spectrum to identify a possible activator.
Summary of luminescence responses:
Fluorite (Mindat) (RRUFF)
- Fluorescence under Longwave (365nm LED) UV light: Blue
- Fluorescence under Midwave (305nm LED) UV light: Blue
- Fluorescence under Shortwave (255nm LED) UV light: Blue