The original birthstone for August was Sardonyx, and then peridot was added, becoming August’s primary gem.
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.
Its name, similarly, combines sard (referencing the ancient Persian city, Sardis, in present-day Turkey, where the red stone was found) with onyx (from the Greek word of the same spelling, which meant “nail or claw.”)
Sard ranges in color from yellowish red to reddish brown, depending on 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.
Measuring 6.5 on the Mohs hardness scale, sardonyx is widely available and relatively inexpensive as gems, beads, and jewelry. It is often carved into cameos, intaglios and brooches to show the color contrast between layers.
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 has been popular for centuries, dating back to the Second Dynasty of Egypt more than 4,000 years ago.
Ancient Greeks and Romans went to battle wearing sardonyx talismans engraved with images of heroes and gods like Hercules and Mars. They believed the stone could harness the bravery of those figures, granting them courage, victory and protection on the battlefield.
Sardonyx was a popular stone for Roman seals and signet rings that were used to imprint wax emblems on official documents—due to the fact that hot wax doesn’t stick to this stone.
Sard was even mentioned in the Bible as one of the stones that adorned the High Priest’s breastplate.
During Renaissance times, sardonyx was associated with eloquence. Public speakers and orators wore it to aid clear thinking and communication.
Unlike rare gemstones that were historically limited to wealthy royals, sardonyx has been popular with elite and regular folk alike. Relatively common and inexpensive, sardonyx is a beautiful and powerful stone that’s affordable enough to join any collection.