Fluorescent Selenite Blades from the Great Salt Plains, Jet, Oklahoma

Contributed by: Chris Clemens
minID: TWQ-UFM
Date: Apr 22nd, 2026
Locality: Great Salt Plains, Salt Plains National Wildlife Refuge, Alfalfa County, Oklahoma, USA (See on Mindat)
Size: 24 x 11 x 57 mm

Description:
The state of Oklahoma is not known to be a prolific source of fluorescent mineral specimens. However, the Great Salt Plains, located in the town of Jet, in Alfalfa County, is famous for producing these well-formed, double-terminated selenite crystals that show moderate fluorescence and phosphorescence under UV. Also known as gypsum, these crystals are unique because they typically contain hourglass-shaped inclusions of brown colored sand. Under UV they show a similar warm tan and pale blue fluorescence under both shortwave and longwave, with blue/green phosphorescence after shortwave and green after longwave UV.

The Great Salt Plains are located in northern Oklahoma, in Great Salt Plains State Park. Collecting these crystals is allowed seasonally from April 1st through October 15th annually.

Originally posted by Chris Clemens on Nature's Rainbows in 2018.

Fluorescence under shortwave UV light.

Afterglow after exposure to shortwave UV light.

Fluorescence under longwave UV light.

Afterglow after exposure to longwave UV light.

Normal light.

Summary of luminescence responses:

Gypsum var. Selenite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: White
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: White
• Fluorescence under Longwave (365nm LED) UV light: Green
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Blue