"Red" Sodalite var. Hackmanite - Deeply Tenebrescent Greenland

Contributed by: Mark Cole
Date: Apr 5th, 2026
Locality: Tunulliarfik Fjord, Ilímaussaq complex, Kujalleq, Greenland (See on Mindat)
Size: 3 x 3 x 4 inches
Weight: 16.9 oz

Description:
Red sodalite is named for the color it takes on when exposed to sunlight; it is nicely tenebrescent under longwave UV. Under shortwave UV the color deepens, in seconds, to almost black in some areas. This is probably the most dramatic example of tenebrescence in sodalite from anywhere. This process is easily reversed in seconds using a bright white light and can be repeated over and over.

Longwave fluorescence is a bright orange/yellow and the shortwave fluorescence shifts to a beautiful rusty orange (caused by the intense tenebrescence). Greenish fluorescence is typical of pieces found in this area within the Ilimaussaq Complex, and has not been identified.

Originally posted by Mark Cole on Nature's Rainbows in 2016.

Fluorescence under longwave UV light.

Fluorescence under shortwave UV light.

Tenebrescence after exposure to longwave UV light.

Tenebrescence after exposure to shortwave UV light.

Normal light.

Summary of luminescence responses:

Sodalite (Mindat) (RRUFF)

• Fluorescence under Longwave (365nm LED) UV light: Orange
• Fluorescence under Shortwave (254nm Lamp/Mercury) UV light: Red
• Tenebrescence after exposure to Longwave (365nm LED) UV light: Purple
• Tenebrescence after exposure to Shortwave (254nm Lamp/Mercury) UV light: Purple