Tenebrescent scapolite from Afghanistan

Shane F. McClure1, George R. Rossman2, James E. Shigley1

1GIA  Research Laboratory
Carlsbad, CA 92008, USA

2Division of Geological & Planetary Sciences
California Institute of Technology, Pasadena, CA 91125-2500, USA


Marialite, a member of the scapolite group, was obtained from Badakhshan, Afghanistan. Unlike most hackmanite which changes from light yellow to pink when exposed to sunlight and UV light, respectively, the Afghanistan scapoilte turns from colorless to deep blue upon exposeure to short-wave UV radiation. It's chemical analysis showed that it contained sulfide: Na4Al3Si9O24Cl0.9S0.09, the ion that is responsible for photochemical color changes in hackmanite and tugtupite.

last updated, Feb 28, 2018