Orange-Red to Yellowish Brown Cordierite from Madagascar

Abstract

Gem-quality cordierite is typically seen as blue material (iolite), showing strong pleochroism in yellow, light blue and dark violet-blue. However, in late 2014 one of the authors (FP) learned about a new occurrence of a much different cordierite, which typically ranged from dark orange-red to yellowish brown. The material is recovered by local miners from weathered residual deposits in southern Madagascar, probably in the Gogogogo area, north of Ampanihy in Tuléar Province. One of the authors (FP) obtained about 120 kg of rough material of mixed quality from the miners over a period of a few months, from which only a few kilograms were suitable for cutting cabochons and faceted stones.