We have a birthday present for those born in August: the stunning spinel has been added to your month’s birthstone lineup! August now joins June and December as the only months represented by three gems. The original birthstone for August was Sardonyx, and then Peridot was added, becoming August’s primary gem. Now Spinel adds its multitude of color choices!
Peridot Overview
Though peridot is widely recognized by its brilliant lime green glow, the origin of this gem’s name is unclear. Most scholars agree that the word “peridot” is derived from the Arabic faridat which means “gem,” but some believe it’s rooted in the Greek word peridona, meaning “giving plenty.” Perhaps that’s why peridot is associated with prosperity and good fortune. Rarely, peridot is also found inside meteorites.
Peridot’s signature green color comes from the composition of the mineral itself—rather than from trace impurities, as with many gems. That’s why this is one of few stones that only comes in one color, though shades may vary from yellowish-green to olive to brownish-green, depending how much iron is present. Most of the world’s peridot supply comes from the San Carlos Reservation in Arizona. Other sources are China, Myanmar, Pakistan and Africa.
Sardonyx Overview
Sardonyx combines alternating layers of sard and onyx—two types of the layered mineral chalcedony—to create a reddish zebra-striped stone with white bands. Sardonyx, like onyx, shows layers of parallel bands—instead of the chaotic, curved bands that compose agate, another type of chalcedony.
The finest examples of sardonyx, which display sharp contrasts between layers, are found in India. Other sources include Brazil, Germany, Czechoslovakia, Madagascar, Uruguay and the United States.
Spinel Overview
The spinel is often assumed to be other gemstones because it tends to resemble either a ruby or sapphire. In fact, some of the most famous rubies in history have turned out to be spinel. But its distinguishing features, like its octahedral crystal structure and single refraction, are what sets it apart from other gems. Significant deposits of spinel have been found in Cambodia, Myanmar, Sri Lanka, and Thailand. It has also been found in Afghanistan, Australia, Brazil, Madagascar, Nepal, Nigeria, Tadzhikistan, Tanzania and the U.S.