Barite - Cave-In-Rock, Illinois

Contributed by: Chris Clemens
Date: Apr 29th, 2026
Locality: Cave-in-Rock Mining Sub-District, Hardin County, Illinois, USA (See on Mindat)
Size: 57 x 37 x 67 mm
Weight: 95 g

Description:
Cluster of white, bladed, barite crystals without matrix, with needle-like, off-white calcite crystals occurring between the central barite blades on one side of the specimen. It was collected from one of the many fluorspar (fluorite) mines in the Cave-In-Rock area of southern Illinois. This barite shows exceptionally bright white to white/blue fluorescence with bright phosphorescence under all UV wavelengths.

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.

Normal light. Side 2.

Fluorescence under longwave UV light. Side 2.

Afterglow after exposure to longwave UV light. Side 2.

Fluorescence under shortwave UV light. Side 2

Afterglow after exposure to shortwave UV light. Side 2.

Summary of luminescence responses:

Baryte (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) 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 (255nm LED) UV light: Blue