World-Class Fluorescent and Phosphorescent Selenite - Manitoba, Canada

Contributed by: FMS Admin
minID: VYJ-GP6
Date: May 11th, 2026
Locality: Red River Floodway, Winnipeg, Winnipeg Metro Region, Manitoba, Canada (See on Mindat)
Size: 10.9 x 6.4 x 11 cm

Description:
Pristine, complete all around, world-class specimen of golden gypsum var. selenite from the Red River Floodway, Winnipeg, Manitoba, Canada. The specimen consists of a "ball" of thin gypsum crystals, surrounded with large, thick crystals radiating from the center, forming a flower-like overall appearance. The specimen is devoid of any damage, and the large crystals show a nice transparency. Brightly fluorescent under all wavelengths, and strongly phosphorescent as well. The longwave UV phosphorescence is green, and the shortwave UV phosphorescence is greenish blue. The color difference between the longwave UV and shortwave UV response is much more subtle.

Originally posted by Frédéric Messier Leroux on Nature's Rainbows in 2022.

Fluorescence under longwave UV light.

Afterglow after exposure to longwave UV light.

Fluorescence under shortwave UV light.

Afterglow after exposure to shortwave UV light.

Normal light.

Summary of luminescence responses:

Gypsum var. Selenite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Blue
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue
• Afterglow after exposure to Longwave (365nm LED) UV light: Green
• Afterglow after exposure to Shortwave (254nm Lamp/Mercury) UV light: Blue