Quarterly Crystal: Unknown Inclusion in Triphane Spodumene
When exploring in the micro-world, we occasionally run into problems we cannot solve and inclusions that cannot be identified. Such was the case with the dominant orange inclusion in this 91.02 ct, 39.29 × 19.34 × 12.93 mm, terminated light yellow triphane spodumene crystal. This spodumene crystal clearly hosts a prominent 4 mm translucent orange crystal surrounded by a stress-related iridescent cleavage halo (figure 1). The spodumene crystal, from Dara-i-Pech pegmatite field, Chapa Dara District, Konar Province, Afghanistan, was acquired from gem and mineral dealer Russell E. Behnke of Meriden, Connecticut. The bodycolor and rounded habit of the orange inclusion (figure 2), together with its origin in spodumene from a pegmatite field, suggested that it might be spessartine. However, laser Raman microspectrometry was not able to pin down the identification of that inclusion. This was because the crystal faces of the spodumene were etched, which interfered with the passage of the laser in the hosting spodumene. As a next step, energy-dispersive X-ray fluorescence (EDXRF) was tried to see if we could pick up any hints of the chemistry in the inclusion. In particular, we were looking for manganese which did show up in the EDXRF scan. Through the microscope, in polarized light, no pleochroism was detected in the inclusion which pointed to the inclusion being isometric. This was as far as we could take the analysis. In order to determine for certain what the unknown inclusion was we realized that destructive analysis would be needed to get a clear identification of the orange inclusion. Since this inclusion specimen was relatively valuable we decided that destructive analysis would not be used, and we would keep the spodumene crystal as it is for future exploration.
