Peridot is a gemstone that was initially mined by the ancient Egyptians on the Red Sea island of Zabargad. This was the source for many of the large peridots in the world’s museums. Known as the “gem of the sun”, Peridot is one of the most valuable gems known for its yellowish green hues. Strongly-colored examples of peridot around the world are spectacular and attractive.
The name of peridot is derived from ‘feridat’, the Arabic word for gem. Peridot is also an idiochromatic gem which means that its color stems from the basic chemical composition of the mineral and not from any traces of impurities. In fact, peridot is one of the gemstones that can be found only in one color even though its shades may vary from light yellowish to dark brownish green.
As the official birthstone for August and the 15th anniversary gemstone, Peridot is found in peridotite rock from the earth’s upper mantle. In 2005, the gemstone was also found in comet dust brought back from the Stardust robotic space probe.
Peridot crystals are found in meteorites and some of the rare extraterrestrial peridot are big enough to facet and cut. Higher quality peridot has an intense color and has extremely high double refraction meaning you can see two of the facets from the pavilion.
While most gemstones are formed in earth’s crust, peridot is formed much deeper in the mantle region. The beautiful yellowish green color is what makes peridot unique and popular. Its crystals form in the magma from the upper mantle and are brought to the surface by tectonic or volcanic activity.
Historically, the volcanic island of Zabargad (St. John) in the Red Sea was home to the most notable deposit of peridot. It was mined for approximately 3500 years before it was abandoned for centuries and then rediscovered in the early 1900s.