We have a birthday present for those born in August: the spectacular 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. Without further ado, let’s welcome the spinel!
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. Spinel also has a lower Mohs hardness than ruby and sapphire.
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.
Vivid red is the most desirable color of spinel gemstones, followed by cobalt blue, bright pink and bright orange. The more affordable stones are often those with paler colors, like lavender. You may also find spinel in black, violet blue, greenish blue, grayish, pale pink, mauve, yellow or brown. So many choices!
When shopping for spinel, a good quality stone should have no visible inclusions. The more inclusions, the less valuable the stone. Spinel can be found various cuts, like octagons, trillions, squares, rounds and fancy shapes, like ovals, pears, and cushions.
Below is a collection of designs featuring the spectacular spinel!
The signature green color of peridot comes from the composition of the mineral itself—rather than from trace impurities, as with many gems. That is why peridot 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.
Also known as “the Evening Emerald” because its sparkling green hue looks brilliant any time of day, peridot is said to possess healing properties that protect against nightmares and evil, ensuring peace and happiness. Babies born in August are lucky to be guarded by peridot’s good fortune.
Peridot can be assessed with the same 4Cs criteria as diamonds—using Color, Clarity, Cut, and Carat weight to determine value. The finest peridots have a lovely lime green hue without any hints of brown or yellow. Quality gems have no inclusions visible to the naked eye, though dark spots may be evident under a microscope. When you look closely, due to double refraction, you may see two of each facet on a peridot.
Whether you’re shopping for an August birthday or a 16th wedding anniversary, be sure to visit an AGS-certified jeweler. They will help you find the perfect peridot design, like those pictured below!
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.
Sard ranges in color from yellowish red to reddish brown, depending how much iron oxide is present. Sard is easily confused with carnelian, another type of chalcedony that is slightly softer and lighter in color.
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.
Used as a stone of strength and protection since ancient times, sardonyx is associated with courage, happiness, and clear communication. Some believe that placing sardonyx at each corner of a house will grant protection against evil.
Sardonyx makes a great gift for people born in August who want something a little different than the traditional peridot birthstone. Readily available and relatively inexpensive, sardonyx makes an affordable addition to anyone’s collection.
The qualify factors of sardonyx are not as clearly defined as other gems like diamonds, so ask an AGS-certified jeweler for help selecting good stones. Generally, the 4Cs still apply.
Sardonyx is widely available and moderately priced in sizes up to 10 carats. The most common cut is cabochon, though it is popularly carved into cameos, intaglios, inlays and broaches to emphasize the contrast between layers.
Artificial and imitation sardonyx has been produced from common chalcedony and plain agate as far back as Roman times, according to writings from first-century naturalist, Pliny. Some gems are also stained with iron oxide pigment or treated with nitric acid to enhance color. These enhancements make stones less valuable than natural sardonyx, so watch for possible imitations when buying these gems.
Want to know more about birthstones? Click here to see all birthstones by month on the American Gem Society website.