A bit late with this one, sorry! August's birthstone is the lovely peridot...Peridot is one of only a few gemstones that only be found in one colour. The depth of colour depends on how much iron is present and can range from yellow-green to olive to brownish green.
Peridot is created in magma in the earths upper mantle, about 25 to 55 miles deep, and bought to the surface by volcanic activity. The only other gemstone that is formed in the mantle is diamond, which is formed much deeper at approx 100-150 miles deep at extreme pressure and temperature.
It is a gem quality variety of olivine and the best quality is found in Mogok in Burma, although other important deposits have been found in Pakistan, Arizona, China and Vietnam. It has alo been found in fallen meteors and also found as olivine on Mars and on the moon!
Peridot is fairly inexpensive in small sizes but over five carats, the price increases dramatically as stones over fifteen carats is extremely rare. Peridots are never treated in any way, that beautiful colour is completely natural.
Also known as "the poor man's emerald", peridot can be found throughout history. The ancient Romans called it "evening emerald" as it's colour didn't darken at night and so could still be appreciated by candlelight. It is also thought that the famous emeralds of Cleopatra were actually peridot. In ancient beliefs, peridot was thought to be a gift from Mother Nature to celebrate the annual creation of a new world.
Napoleon used peridot to assure Josephine of his undying love and admiration.....just before he had the marraige annulled - typical!