GIA: Library: Peridot

Peridot has always been associated with light. The Egyptians called it the "gem of the sun." Some believed that It protected its owner from "terrors of the night," especially when it was set in gold. Others strung the gem on donkey hair and tied it around the left arm to ward off evil spirits. Today, Arizona's San Carlos Indian Reservation is the world's most commercially important producer.

Peridot is usually transparent. It comes in an attractive range of colors, from brownish or yellowish green to greenish yellow. Customers will be attracted to the bright lime greens and more subdued olive greens of this lovely gem. This gem is relatively inexpensive and plentiful, and normally available in standard shapes and calibrated sizes up to about 5 cts. Larger stones are also fairly easy to find. Tumbled and faceted peridot is used for bead necklaces and bracelets, often combined with gems in contrasting colors — amethyst, citrine, and pink tourmaline, to name a few.

The word peridot comes from the Arabic faridat, which means "gem." Most peridot formed deep inside the earth and was brought to the surface by volcanoes. Some has also come to Earth in meteorites, but this extraterrestrial peridot is extremely rare, and you're not likely to see it in a retail jewelry store. Mineralogists refer to the stone as olivine.

Peridot is one of the US birthstones for August (sardonyx is the other).

Sources

Sources for peridot include Myanmar (Burma), Pakistan, and the United States

Hardness & Toughness

Peridot has a hardness of 6.5 to 7 on the Mohs scale, and a toughness that ranges from fair to good.

Stability

Rapid or uneven heat can cause fracturing in peridot. The gem is stable to light, but is attacked easily by sulfuric acid, and less easily by hydrochloric acid. Long-term exposure of perspiration may also attack peridot.

Care and Cleaning

Warm, soapy water is recommended to clean peridot. Steam cleaning should never be used, and ultrasonic cleaning is risky.

Imitations

Glass, plastic, synthetic sapphire, and synthetic spinel have all been used as peridot imitations.