August 2, 2012

August Birthstones

By Eloise Graham

The most popular birthstone for August, peridot (pronounced pair- a – doe,) is a gem primarily made up of two minerals: fayalite and forsterite. Fayalite has a high iron content and forsterite a high magnesium content. It is the iron that gives the stone its greenish hue.

Peridots have probably been mined for over 4,000 years. Myanmar (Burma) and other places in the Far East probably produce the best quality gems. However, Arizona produces the largest quantity of stones. Most of the worlds supply comes from Arizona.

Throughout history, peridots have been confused with other gems. Many “emeralds” of royal treasure have been found to be peridots. The emerald is a deep, dark green, while the peridot is a soft yellow green. It is the iron that will give it the yellowish tone. The best peridot will have no more than 15 percent. Some jewelers refer to the peridot as the “evening emerald.”

Peridot is a beautiful gemstone in its own right and is widely popular. Its popularity is increasing yearly. There are new finds in Pakistan producing exceptionally well crystallized specimens.

A less common birthstone for August is the sardonyx. Sardonyx is a form of onyx recognized by its layers of reddish brown and white banding. It was popular with the ancient Greeks and Romans, who carried into battle talismans of sardonyx engraved with images of heroes, such as Mars or Hercules. Because of its attractive banding, sardonyx has long been used to fashion cameos and intaglios (the reverse of cameos). This gemstone is found throughout the world. The most attractive specimens are found in India, but material also is mined in Czechoslovakia, Brazil, Uruguay, Germany, and in the United States.