August birthstones
August has three birthstones: Peridot, Spinel and Sardonyx. GIA names Peridot as the main stone; the American Gem Society lists all 3.
A gem form of the mineral olivine, one of the few gems found in only one color family: green.
It was mined on Egypt's Zabargad Island in the Red Sea and called the "gem of the sun".
A hard, durable gem that is often mistaken for ruby or pink sapphire. Added as an August birthstone in 2016.
Spinel was confused with ruby until 1783; the "Black Prince's Ruby" in England's Imperial State Crown is a spinel.
A banded chalcedony quartz with alternating layers of sard and onyx, used for jewelry, seals and cameos.
Greek and Roman warriors wore engraved sardonyx talismans for courage and protection.
Pick by color, budget and how the piece will be worn. Harder, tougher stones suit rings worn every day; softer ones last longer as pendants or earrings.
| Stone | Mohs | Everyday wear | Warm soapy water | Ultrasonic |
|---|---|---|---|---|
| Peridot | 6.5 to 7 | Wear with care | Safe (the best method) | Not recommended |
| Spinel | 8 | Good for everyday wear | Safe | Usually safe (fractures can be a problem) |
| Sardonyx | 6.5 to 7 | Wear with care | Warm water, mild soap and a soft cloth or brush | Not covered by AGS |
Compare: Peridot vs Spinel · Peridot vs Sardonyx · Spinel vs Sardonyx
The right piece depends on how tough the stone is. These suggestions follow GIA's hardness and toughness notes for each stone.
| Stone | Best as | Why |
|---|---|---|
| Peridot | Pendants and earrings, or a protected ring | Can chip or scratch, so a pendant or earrings is the safer gift. For a ring, choose a protective bezel setting and occasional wear. |
| Spinel | Rings, pendants and earrings | Durable for most jewelry, including rings, with a little care. Take rings off for heavy work. |
| Sardonyx | Pendants and earrings, or a protected ring | Can chip or scratch, so a pendant or earrings is the safer gift. For a ring, choose a protective bezel setting and occasional wear. |
See every month in our birthstone gift guide by month.
Before the US list was standardized in 1912, the traditional stones for August were: Sardonyx, carnelian, moonstone, topaz. How the list changed.
Peridot, Spinel and Sardonyx. A gem form of the mineral olivine, one of the few gems found in only one color family: green.
Peridot: vivid green with slight golden undertones. Spinel: vivid red. Sardonyx: bands of reddish brown, cream, black and white; clean, well defined layers are valued most.
Extra stones were added to the US list by jewelry trade groups to give more choice of color and price (in 1952, 2002 and 2016). Spinel was added in 2016.
Spinel is 8 on the Mohs scale (good for everyday wear). Peridot is 6.5 to 7 on the Mohs scale (wear with care). Sardonyx is 6.5 to 7 on the Mohs scale (wear with care).
Sources: American Gem Society: Birthstones, GIA: The Beauty of Birthstones, and the GIA care guide and AGS overview for each stone (linked on its page). Checked October 16, 2026.
Birthstone of the month
On the first of each month: that month's birthstone, what it means and how to care for it.
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