Fluorescent Barite - Elk Creek, South Dakota

Contributed by: Chris Clemens
Date: Apr 29th, 2026
Locality: Elk Creek, Meade County, South Dakota, USA (See on Mindat)
Size: 47 x 38 x 66 mm
Weight: 86 g

Description:
Sprays of golden amber barite crystals cover a dark chocolate brown matrix in this specimen from the Elk Creek area of Meade County, South Dakota. Under both short and long wave UV the barite fluoresces a creamy white color and phosphoresces blue/green after short wave and green after long wave. The Elk Creek area is notable for producing golden-amber colored barite crystals that are fluorescent under all UV wavelengths. The primary occurrence of this material is located along the bank of Elk Creek in the Black Hills of Western South Dakota, where the barite crystals have formed within the hollow interiors of calcareous concretions found in the surrounding Cretaceous age shale.

Originally posted by Chris Clemens on Nature's Rainbows in 2017.

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:

Baryte (Mindat) (RRUFF)

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