Geographic Origin Determination of Emerald

Abstract

GEMS & GEMOLOGY WINTER 2019 When the Spanish conquistadors first brought Colombian emeralds (figures 1 and 2) onto the international market, they became a global sensation in their day. Emeralds from Central Asia and Egypt were known at the time, but the world had likely never seen emeralds of such high quality and size. Traders soon developed distribution channels that brought the Colombian material all the way from the royal courts in Europe to the powerful Moguls of India (Giuliani et al., 2000). The nineteenth and twentieth centuries saw all of this change as new mines sprang up around the world to challenge the famed Colombian emeralds. Most notable in terms of high-quality production were Brazil, Russia, and Zambia, but smaller deposits have been uncovered in Madagascar and Ethiopia and elsewhere. As the market has evolved alongside these developments, geographic origin has come to be an important factor for fine-quality emeralds. The demand for emerald origin determination was initially driven by the proliferation of sources. However, this expansion and diversification of emerald sources has also complicated origin determination. As the number of sources grows, so does the overlap in their characteristics. The following sections will detail the specific criteria used in the laboratory at GIA to make geographic origin conclusions for emeralds, as well as potential areas of overlap and how these are dealt with.