Olmiite – N'Chwaning II Mine, South Africa

Contributed by: FMS Admin
Date: May 9th, 2026
Locality: N'Chwaning II Mine, N'Chwaning Mines, Joe Morolong Local Municipality, John Taolo Gaetsewe District Municipality, Northern Cape, South Africa (See on Mindat)
Size: 2.5 inches

Description:
A small olmiite and calcite from the N'Chwaning II Mine in South Africa. The olmiite fluoresces a deep red, in all wavelengths. The calcite in this piece does not fluoresce at all.

Originally posted by Fire Viper on Nature's Rainbows in 2017.

Fluorescence under longwave UV light.

Fluorescence under shortwave UV light.

Normal light.

Summary of luminescence responses:

Olmiite (Mindat) (RRUFF)

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