Emeralds: What's behind the Green?
If you were born in May, consider yourself fortunate. The May Birthstone, Emeralds are known to bring fortune to its owners and have been revered for thousands of years. Queen Cleopatra of Egypt used Emerald in her royal adornments, as her favorite color was the lush green you find in gem-quality emeralds. The Inca people also traded emeralds for over 500 years before Spanish conquests in the 1600’s, when King Cortez fell in love with the vivid green gemstones and brought them to Medieval Europe, where they were sent across Europe and continued to gain admiration and reverence.
Emerald quality, as with other precious gemstones, lies with the intensity of an emerald’s color. Vivid green emeralds will command the most attention, while bluish-green or dull colored stones are not as esteemed. Clarity is important as well, as stones with less inclusions are highly sought after, since emeralds are often quite included. Carat size is also highly relevant, as a 10 carat stone of a certain quality will sell for more than double that of a 5 carat stone of the same quality, even though it is exactly double the size.
The amount of “oil” treatment– a process where certain types of oils are seeped into the fissures of an emerald, filling inclusions and cracks in order to improve color and clarity– is instrumental in valuing an emerald. Gemological labs will test for the presence of oil and the amount, providing a grade scale of “Major–Moderate–Minor–Insignificant–None” for oil treatment, with minor oil considered acceptable for auction-quality emeralds. Emeralds with no oil are clearly worth more than those with oil, though only if the quality and beauty of the stone remains high.