Rhombohedral calcite group exhibiting organic fluorescence

Contributed by: FMS Admin
Date: Sep 19th, 2025
Locality: Beez quarry, Namur, Namur, Wallonia, Belgium (See on Mindat)

Description:
Rhombohedral calcite group, Beez, Namur, Belgium. It exhibits the typical yellow-green fluorescence and afterglow (PeL image). At shorter excitation wavelengths, the color becomes more greenish due to a shift in emission maximum. Black full: 365 nm excitation. Black dashed: 275 nm excitation.
Originally posted by groensteenfreterke on Nature’s Rainbow.

Fluorescence under longwave UV light.

Fluorescence under 275nm UV light.

Afterglow after exposure to longwave UV light.

Normal light.

Fluorescence spectra.

Summary of luminescence responses:

Calcite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Yellow
• Afterglow after exposure to Longwave (365nm LED) UV light: Green