Before all of our modern chemistry, stones were classified by color. All red stones were rubies and all green stones were emeralds. Emeralds which we now know to be Peridot, were mined on St. John's Island in the Red Sea as early as 1300 B.C. At that time the island was known as Topazios, and the green gems called topaz. Egyptian kings greatly prized this gem. It was said that the island was often hidden by a very dense fog and was lost for centuries. Peridots are believed to have the power to break evil spells, dispel the mysteries of the dark, promote healing of insect bites and to help in liver ailments. During the Middle Ages, people wore Peridot to gain foresight and divine inspiration.