Large Namibian Demantoid Garnet
Namibian demantoid was first discovered in the 1990s (Fall 1997 GNI, pp. 222–223). The current production came from an open-pit, hard rock mine with an annual production between 5,000 and 10,000 carats. According to Reif, the local geology includes marble, pegmatite, and rhyolite. The distribution of demantoid pockets within these rocks is irregular and difficult to predict. Beside the geological challenges, water is scarce, and temperature extremes range from freezing at night to baking desert heat in the daytime.
The Green Dragon mine is renowned for its production of well-proportioned rough. This material is suitable for cutting smaller gems into 2–3 mm sizes in a range of colors from slightly bluish green through “lemongrass” green to greenish yellows and reddish browns. These are used for precision-cut calibrated and melee-sized goods placed as accent stones in high-end jewelry. Most of the cutting is done in Thailand, and the yield is approximately 10% due to the desire for well-proportioned cut gems. Besides precision-cut demantoid and andradite garnet in calibrated sizes, Reif also cuts to higher tolerances for the watch industry, producing 3 × 2 mm tapered baguettes for watch bezels.
Even in these small sizes, well-cut gems display high luster and very distinct fire, making them an excellent visual alternative to diamond. Rough suitable for gems of 6.0 mm (about 1 ct) is much rarer, but material for larger gems does come up once in a while.
