Micro-World Gems & Gemology, Spring 2016, Vol. 52, No. 1

Iridescent Inclusions in Scapolite

Orange color and aventurescence in scapolite
Figure 1. Orange platelet inclusions give this 2.21 ct scapolite an orange color and aventurescence similar to that of Oregon sunstone. Photo by Jonathan Muyal.

A 2.21 ct phenomenal scapolite (figure 1), reportedly from Tanzania, was recently examined by this author. Of particular interest was its striking resemblance to Oregon labradorite feldspar, which displays aventurescence and is known in the trade as sunstone. Raman microspectrometry confirmed the stone’s identity as scapolite. Vibrant thin-film iridescence created by brownish orange exsolution platelets (figure 2) was revealed by microscopic examination; these platelets are responsible for the stone’s orange bodycolor. The exsolution platelets are presumed to be hematite based on their color, morphology, and high levels of iron detected by energy-dispersive X-ray fluorescence (EDXRF), although it was not possible to confirm this identity through Raman analysis. This scapolite’s aventurescence and pleasing orange bodycolor make it an interesting collector’s gemstone. 

Platelets in scapolite reveal iridescence
Figure 2. Under magnification with oblique illumination, the platelet inclusions reveal vivid multicolor iridescence. Photomicrograph by Jonathan Muyal; field of view 1.42 mm.

Jonathan Muyal is a gemologist at GIA in Carlsbad, California.