Gem News International Gems & Gemology, Spring 2018, Vol. 54, No. 1

Update on the Green Dragon Demantoid Mine in Namibia

Namibian demantoid from the Green Dragon mine, preserved in host rock
Figure 1. Namibian demantoid retrieved from the Green Dragon mine and preserved in its host rock. Photo by Albert Salvato.

According to Stephan Reif, Namibia’s Green Dragon mine is the largest continuously operating demantoid deposit. Green Dragon has a complete mine-to-market approach, handling everything from mining, ore processing, sorting, cutting, and grading to wholesale. They mainly supply the European market through Vienna and the Asian market through Hong Kong.

The mine was discovered in a remote part of southern Namibia in the 1990s and has been producing since the mid-2000s. In 2017, Green Dragon received a 25-year mining license for the deposit, offering stability as an incentive to invest in the mine. In the near future, mining will be scaled up and production will increase. This will provide a more consistent and attractive supply for buyers in the trade. As part of the 25-year mining lease, Green Dragon has committed to supporting the local communities.

Operations at the Green Dragon Mine
Stephan Reif provides an update on the activities at southern Namibia’s Green Dragon demantoid mine.

Namibian demantoid mining is highly mechanized, using heavy equipment to extract the green garnets from their host rock (see figure 1). Monthly production varies between 15 and 20 kg. Of that, a little over 10% is considered gem quality and goes for faceting.

Color ranges from yellowish green to bluish green, and some darker brownish greens are also found. Demand for certain colors varies, but at the moment the yellowish “golden” colors are in highest demand by designers. For Reif, the ideal Namibian demantoid is a slightly bluish green gem full of fire and brilliance.

Light color and high dispersion of Namibian demantoid
Figure 2. The cutting and polishing of Namibian demantoid should emphasize the material’s lighter color and high dispersion. Photo by Albert Salvato.

The combination of lighter color and very high dispersion sets Namibian demantoid apart from other green garnets. These properties also depend on the quality of cutting and polishing (figure 2), something Green Dragon has focused on in recent years by having their in-house lapidaries and quality control perform to a higher standard. Because clarity, color, and calibration standards are so tight, the yield is only around 9%.

Most of the production is in melee and small calibrated sizes, with fine singles being extremely rare. Fine-quality melee is in very high demand in Europe at the moment, especially in the 4.0–6.5 mm range. In recent years, the demand for very small melee (1–2 mm) has increased substantially. Larger exceptional pieces typically go to Asia.

Wim Vertriest is supervisor of field gemology at GIA in Bangkok.