Feature Gems & Gemology, Fall 2012, Volume 48, No. 3

Tsavorite and Other Grossulars from Itrafo, Madagascar

Since 2002, tsavorite and other grossular varieties have been recovered from a primary deposit at Itrafo, a village in the Andrembesoa area of central Madagascar. Twenty-two samples from this locality were investigated by classical gemological methods, chemical analysis, and UV-Vis-NIR and mid-IR spectroscopy. The garnets’ chemical composition was nearly pure grossular (92 mol. %), with iron and vanadium as the main chromophores. Their iron content and Fe2O3:V2O3 ratio were higher than those generally found in tsavorite from well-known deposits. Although the Itrafo deposit is relatively large, and new veins could be discovered, future production will be limited by access difficulties and security concerns.