Leucophanite, Sodalite, etc. - Greenland

Contributed by: Michael Crawford
Date: Jun 21st, 2026
Locality: Tunulliarfik Fjord, Ilímaussaq complex, Kujalleq, Greenland (See on Mindat)
Size: 11 x 11.5 cm

Description:
Sodalite (Na₄(Si₃Al₃)O_{12>/sub>Cl) and leucophanite (NaCaBeSi₂O₆F) dominate the fluorescent minerals in this specimen. The specimen comes from Tunuliarfik, Ilimausaq Complex, Greenland. The colors of the two dominant fluorescent minerals are best seen together under midwave UV illumination. The brightness of the leucophanite in this specimen is considerably dimmer compared to leucophanite from Norway, Mt. St. Hilaire, and Tajikistan. Like leucophanite from these other locations, the fluorescence is much brighter in the ultraviolet region compared to the visible fluorescence. This ultraviolet fluorescence is likely activated by cerium and possibly other rare earth elements. However, the visible fluorescence in this specimen is different from the other locations. This leucophanite only fluoresces under MW light. Leucophanite from the other locations fluoresces under LW and SW light. Also, the MW fluorescent color is more violet compared to the pink color of leucophanite from the other locations. This suggests there is little manganese activating red emission in this leucophanite compared to other leucophanites.

False color images of the ultraviolet fluorescence show that the leucophanite fluoresces in the ultraviolet region under MW illumination, but there is no ultraviolet fluorescence under SW light. The leucophanite has a cyan color in the MW false color image. Sodalite appears as red and gray, and an analcime crystal is white in the MW false color image. The dim yellow brown colors in the SW false color image are from weak sodalite and analcime fluorescence in the ultraviolet.

The midwave emission spectra of leucophanite show differences in the number of ultraviolet peaks and their positions. There are four peaks in the spectra from the four locations (348 nm, 356 nm, 367 nm and 381 nm). The following table shows how the peaks vary for each location.}

Location	348 nm	356 nm	367 nm	381 nm
Greenland	no	YES	YES	no
Norway	YES	no	YES	no
MSH Canada	no	YES	YES	YES
Tajikistan	no	YES	YES	YES

It is not known what causes these differences.

The LW emission spectrum of sodalite shows the typical vibronic signature caused by disulfide replacing chlorine in the sodalite cage. Under MW and SW UV light, the fluorescence becomes red due to ferric iron (Fe³⁺) replacing aluminum (Al³⁺). The MW spectrum has a broad peak with a maximum at 619 nm. The SW fluorescence is not bright enough to measure a spectrum.

Under SW illumination, the specimen lights up with numerous grains of a green, fluorescent mineral. The emission spectrum shows the fluorescence is activated by the uranyl ion (UO₂²⁺). The mineral may be chkalovite. The radioactivity is around 100 cpm.

There is an analcime crystal in the center of the specimen that is bluish white under MW and SW and dim light blue under LW.