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Emerald for May by Harry W. Short, Engineering Geologist Emerald, the May birthstone, is a form of beryl as was aquamarine, the March birthstone. The name is derived from the Greek word “smaragdus,” meaning green. Emeralds have been mined in Egypt since around 330 B.C. The mines, called Cleopatra’s Mines, were developed on the earth’s surface and in crude underground workings. Cleopatra and other monarchs of the era adorned themselves with the highest quality emeralds. The mines were eventually lost in time, forgotten for centuries and became thought of as legends. The mystical mines were rediscovered by a man named Cailliaud in excava- tions at Pompeii and Herculaneum, and were reopened in 1819. Cailliaud’s mining venture failed; but at a later date buckets of emerald-bearing rock were found, where the ancient miners had apparently left them near an area known as Wadi Chamal. Two groups of old mines were found 15 miles from there, about 10 miles apart. Hundreds of old shafts had been driven into a hard, dark mica schist (metamorphic rock) in the hills. Many were large enough to hold 400 men who were supposedly criminals or slave laborers. The emerald variety of beryl contains various shades of green and is a complicated silicate of beryllium and aluminum. Its beautiful green color is derived by a small amount of chromium oxide within the mineral structure. Its hardness is 7.5 to 8, has an index of refraction from 1.57 to 1.60, with a specific gravity of 2.75 to 2.80. Emerald crystallizes in the six-sided hexagonal system with poor cleavage in one direction. Emeralds and beryl are usually found in granitic rocks or associated pegmatite dikes. New England, North Carolina, the Ural Mountains in Russia and Brazil have produced numerous beautiful emerald specimens. The finest emeralds come from Columbia. In ancient times, the emerald was held in great esteem because it was believed the pretty colored stone sharpened a per- son’s eyesight and mind. Early engravers kept emeralds on their workbenches to gaze on to rest their eyes; travelers believed the emerald protected them from hazards. It’s also been said colorful emeralds have the ability to uplift a person’s spirit on sight, give the wearer power of insight into the future, and bring good fortune, youth, and rebirth. Thus, this gemstone is a gift to be treasured forever for its beauty and purported mythical powers. Harry In memory of Harry Short. His articles will continue posthumously. Contact: michele@worldwidedrillingresource.com Gachala emerald photo by Chip Clark. 53 WorldWide Drilling Resource ® MAY 2016