The birthstone for May is the emerald, which gets its name from Greek, Old French, or Sanskrit words meaning "green gemstone." Emeralds have been mined since 1500 BC in Egypt, India, and Austria. They are a variety of beryl containing beryllium, aluminum, silicon, oxygen, and forming six-sided symmetrical crystals. Emeralds range in color from light to dark green and their main producers are Colombia and Zambia. They are believed to have healing properties and were symbols of nature, resurrection, and foresight. Emeralds are graded based on their color, cut, clarity, and crystal structure.