Long valued for its beauty and allure, the history of the emerald reaches across the ages and spans civilizations, from the Babylonians and Egyptians to the Romans and Aztecs. Embraced by rulers, the likes of Nero, Cleopatra, and many crowned heads of Europe, the emerald has experienced a popularity that ranks it high amongst royalty. Owing to the gem’s intensely green color, which has been referred to as “green fire,” the emerald has been ascribed both healing powers and mythological associations, such that ancient Egyptians dispatched their mummies to the next world with an emerald draped about the neck as a means of eternal youth. Even the emperor Shah Jahan, builder of the Taj Mahal, was believed to have the collected emeralds as talismans.
The spectacular verdant green that comprises the emerald and has made it one of the most prized gemstones in existence can be attributed to trace amounts of chromium, vanadium, and iron. As a member of the mineral group Beryl, the emerald is the most valuable gem in its category, although classification requires, among other things, that the green be medium or dark in tone. The color of the emerald usually ranges from a rich, saturated green to a vibrant green with undertones of blue. Adding to its uniqueness is the fact that these stones are generally highly included, making those that contain fewer inclusions the rarest.
Emeralds have been discovered in a host of countries throughout the world, but are mined most notably at present in Columbia and Zambia, both of which produce emeralds of superior quality. When Zambian emeralds initially hit the international market, the rough crystals produced such clean stones that dealers initially believed they were synthetic. In time, the clarity of the Zambian emeralds generated expectations for clearer emeralds overall, consigning a large share of the emerald market to Zambia.
The primary mine responsible for producing Zambian emeralds is the Gemfields Kagem Mine, the single largest emerald producing mine in the world, located in the northwest portion of the country. The mine contains six known belts of Talc-Magnetite Schist (TMS), a 1.6 billion-year-old high-grade metamorphic rock, the Fwaya Fwaya-Pirala belt presently being the main area of extraction. It was due to unique conditions prevalent at the time during which the TMS came into contact with a younger, intruding pegmatite of 500 million years that helped these beautiful stones mineralize and take shape. The chemical interaction between the pegmatite and the TMS brought about a soft, thin black reaction zone where the emerald fluids collected and were allowed to crystallize into its perfectly hexagonal shape. The metamorphic TMS provided the trace element—chromium—which had been absorbed into the emerald, resulting in the rich and saturated green color of this rare gem. Don’t be fooled, however, it still took many millions of years for the formation to occur!
The area within which the mine is located is a region situated within the basins of two rivers: Kafubu and Kafue. Beryl was originally discovered at what is now known as the Miku mine in 1928, and the region was then subjected to a number of investigations between 1940 and 1950. Limited mining for emerald-beryl commenced in 1967 and, after a formal Geological Survey of the region, State-owned Mindeco took over this operation in 1971.
Several new locations were later discovered and exploited by local artisanal miners, which led to additional prospecting and disorganized surface mining both by Mindeco and private operators. In 1977, Mindex, the exploration arm of Mindeco, commenced systematic exploration of the area. During the same period, the activities of the small-scale miners expanded to uncontrollable proportions to the extent that by the end of 1978, the Government closed off the entire area to prospecting and mining by outside parties.
In 1980, the Government of Zambia established the Reserved Minerals Corporation to conduct and coordinate exploration and mining, either for the state or in cooperation with private companies. The Ndola Rural Emerald Restricted Area, extending to some hundreds of square kilometres, was later established. Those deposits with the greatest potential were grouped into the Kagem Mining Company, which is today owned by Gemfields and the Government of the United Republic of Zambia.
Mining at the Kagem mine is performed in an opencast fashion—that is, in an open pit formation. Following controlled blasting of the host rock, experienced chiselers work through the reaction zone to extract the emeralds. The utmost care is exerted during this process in order to avoid damaging the crystals. The material extracted from the pit is collected by excavators and unloaded at a washing plant, whereupon the ore is washed and the rough emerald is cleaned, sorted and graded.
The emerald rough produced by the mine is marketed through closed tenders as natural, untreated gems. The world’s top gem houses and emerald lapidaries are invited to attend these tenders, which are hosted three to four times a year. Schedules are granted to the highest bids to exceed the undisclosed and pre-determined minimum reserve prices. The first tender, hosted in July 2009, drew thirty companies from several different countries. Nearly 1.4 million carats were offered, amounting to $5.9 million USD. Now, both interest and demand are increasing at an exponential rate at all of the company’s more recent tenders.
Indeed it’s been a long haul for the beautiful Zambian emerald, but it appears from the interest and demand now being generated that it was well worth the wait—this for a gem of such magnificence and beauty, and one that possesses a long and comprehensive history.