Emerald is the green variety of the mineral beryl and birthstone for the month of may it has been the worlds most popular green gemstone for over 5000 years. There is a great little chapter on research in laryngology which s diagnosis and treatment of voice disorders now in its fourth edition continues to serve as a definitive reference for students and professionals in the fields of otolaryngology speech language pathology voice and singing and related sciences. Emeralds are a green to greenish blue variety of the gem species beryl be3al2 si6o18 its color can come from minute amounts of either chromium or vanadium they are a hard but brittle gem as flaws are common in their formation emeralds form both naturally and through manmade conditions manmade emeralds are . In 2000 a 1011 ct columbian emerald was sold for 1149850 zachovay 2002 to understand emerald we need to first understand the physical and chemical structure of beryl be3al2si6o18 emerald colour is caused by trace element of chromium cr and or vanadium v replacing the aluminium al in the crystal structure
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