I like to collect fluorescent rocks that also tell a story about their formation. This is a sodalite specimen from Sar-e-Sang, Badakhshan, Afghanistan. This sodalite specimen has been brecciated and the voids were filled white dolomite. The dolomite identification is from XRD analysis. The dolomite also contains grains of light brown titanite/sphene.
The emplacement of the dolomite-titanite modified the visible and fluorescent properties of the sodalite. The original sodalite has a blue color. The fluids that deposited the dolomite and titanite altered the sodalite to a violet color. Several of blue sodalite clasts have a reaction rim of violet sodalite where they are in contact with the dolomite. Additionally, longwave UV fluorescent response of the altered sodalite is slightly different. The peak fluorescent response is shifted to longer wavelengths (see Picture 7). The altered sodalite became phosphorescent and tenebrescent. Titanium from the dolomite fluids penetrated into the sodalite clasts and is the likely activator for the phosphorescence. The reaction rims are clearly shown in the phosphorescent i