Learn About Emerald Gemstones

Emerald Gemstone Properties
Known in the gemstone trade as one of the “big three” along with ruby and sapphire, a
fine loose emerald gemstone is a fascinating gemstone. As a member of the beryl family along with Aquamarine and Morganite, Emerald shares the beryl families’ common physical properties such as good durability, hardness (8), but moderate brilliance and luster. . In contrast to other beryl gemstones, emerald is typically heavily flawed with cracks and inclusions of fluid and minerals. These inclusions are called "jardin" (or garden), as the inclusions resemble leaves and branches. The processing of an emerald gemstone is more challenging due to the tendency for emeralds to be brittle and containing cracks and fissures, which often come to the surface of the gem. Skilled gemstone cutters often study high value emerald rough for some time before cutting the gem rough. This is more true for Columbian rough emeralds and less so for their African cousins. Emeralds are almost always treated to seal the gemstone. This sealing process fills the fissures and cracks with resin or fluids that not only seal but also hide these fissures to make them less noticeable to the eye. This seal should be protected. The cleaning of emeralds also represents challenges due to the gemstones brittleness and typical presence of surface cracks. Emeralds should never be cleaned in an ultrasonic cleaner and emerald jewelry should always be removed before washing hands in any kind of soap or cleaning agent.

Emerald Gemstone History and Lore:
Emerald has one of the longest histories of all gemstones. The word emerald derives from the Greek word "smaragdos". Mining tools found at the entrance to ancient emerald mines date back to ancient Egyptian pharaohs, dating at least as far back as 1500 BC. When the Spanish invaded South America, the conquistadors observed the native rulers wearing them. In 1537 the Spanish discovered the famous Chivor and Muzo mines, in what is now Colombia. Because of the ancient history of emerald gemstones, many of the finest emeralds ever discovered ended up adoring the jewelry of kings, maharajahs, shahs and queens. The “Mogul of India dates from 1695, weighs 217.80 carats, and is some 10cm tall. One side of it is inscribed with prayer texts, and engraved on the other there are magnificent floral ornaments. It is one of the finest examples of ancient emeralds.

Emerald Gemstone Sources and Occurrences:
The main sources for fine quality loose emerald gems from African are Zambia, Zimbabwe, Tanzania and Madagascar. Traditionally Colombia has been the world's largest producer of high quality emeralds. In recent years, new emerald mines in Brazil are producing spectacular emeralds of impressive sizes. Brazil is also the world’s largest producer of commercial quality emeralds gems. Russia, Pakistan, Afghanistan and India are also significant producers of fine quality and commercial gems. African emeralds typically form in the contact zone between mica schist and a pegmatite. The mica schist provides the chromium or vanadium that is responsible for the emerald’s luminosity of color. As a consequence, African emeralds typically have mica inclusions. Colombian emeralds are formed hydrothermically in vugs in calcite and quartz veins. As a consequence of this geological environment, Columbian emeralds typically have three phase inclusions of gas, liquid and crystal.

Emerald Gemstone Evaluation and Valuation
As with most other colored gemstones; color is the most important consideration when evaluating emerald. A rich, luminescent velvety green color , uniform throughout the stone, is what every emerald lover dreams of. Colombian stones typically have a secondary yellow color and the African stones have a more bluish secondary color to them. Clarity is a secondary evaluation criterion for emerald. Extremely fine emeralds worth millions of dollars can contain eye visible inclusions. Because emerald is so valuable, there are many fakes and synthetics on the market. Any important emerald should always be purchased with a gemological certificate from a reputable gemological laboratory. Of course a reputable gemstone trader will provide the necessary guidance to assist in this purchase process. Almost all emeralds are oiled to help hide cracks and inclusions. Oiling with a colored fluid, to improve the color, is considered fraudulent treatment.