Quick Answer
August has three official birthstones: peridot, spinel, and sardonyx. Peridot is the modern and best-known choice, a vivid yellow-green gem formed deep in the earth's mantle. Spinel is the newest addition, joining the list in 2016, and comes in red, pink, blue, and lavender. Sardonyx, the traditional stone, is a banded reddish-brown and white gem once prized for engraved seals.
What Are the August Birthstones?
August is one of a handful of months with more than one birthstone. Peridot has long been the modern standard, sardonyx anchors the older, traditional list, and spinel is the newest name added to the roster — official as of 2016, when the American Gem Trade Association and Jewelers of America recognized it alongside peridot.
- Peridot — a yellow-green gem variety of the mineral olivine, one of the few gemstones that occurs in essentially a single color family
- Spinel — a durable gem that comes in red, pink, blue, and lavender, long mistaken for ruby and sapphire in historic jewelry
- Sardonyx — a banded chalcedony combining reddish-brown sard with white or black onyx layers
Peridot: August's Signature Green Gem
Peridot is the gem form of olivine, colored by iron rather than the trace elements that tint most gems, which is why nearly every peridot reads yellow-green to olive. It measures Mohs 6.5 to 7, softer than everyday-wear stones, and it's one of the rare gems also found in meteorites alongside its usual volcanic origins.
- Untreated in almost all cases — peridot's color comes naturally, with no routine heating or filling to disclose
- Sensitive to sudden temperature swings and harsh chemicals, so skip the ultrasonic cleaner and remove it before hot showers
- Best suited to pendants and earrings that see gentler daily contact than a ring worn on the working hand
Spinel and Sardonyx: The Other Two August Stones
Spinel and sardonyx round out August's list with very different stories. Spinel spent centuries mistaken for ruby and sapphire in royal jewelry before mineralogists identified it as its own gem; sardonyx has been carved into seals and cameos since ancient Rome, prized for a hardness that held fine detail.
- Spinel sits at Mohs 8, tough enough for daily wear, and appears in red, pink, blue, and lavender — lab-created spinel is common in birthstone jewelry and should be labeled honestly when used
- Famous historic "rubies," including the Black Prince's Ruby in the British Crown Jewels, later turned out to be spinel
- Sardonyx is a form of chalcedony around Mohs 6.5 to 7, valued for its straight, contrasting bands of color
How to Wear an August Birthstone Look Every Day
An August birthstone tends to work best as a pendant or a pair of studs rather than a ring in daily use, especially for softer peridot. Layer a birthstone-inspired pendant with a plain chain, or add a personal touch with an initial or a zodiac piece, since Leo and Virgo both fall within August's calendar.
Here's what we make in moissanite and 925 sterling silver for that everyday layer — a sparkling companion piece, not a birthstone substitute:
Browse the full necklaces collection for more everyday pendant styles, or see our gift guide under $100 for more ideas.
A Custom August Birthstone Piece, Made to Order
A birthstone usually means more when it's tied to a specific person rather than just a calendar month. We build made-to-order pieces around that idea: an initial pendant with a genuine August birthstone accent, a small design for a milestone, or a piece made for one gift and nobody else's.
An initial pendant like this is a natural starting point for a custom design conversation, not a birthstone piece on its own. Start a custom design inquiry and tell us what you have in mind — we'll talk through sourcing options for a genuine peridot, spinel, or sardonyx accent.
Caring for August Birthstone Jewelry
August's three birthstones call for slightly different care because of how their hardness varies. Peridot is the softest of the three and the most reactive to heat and chemicals, spinel is tough enough for daily wear, and sardonyx holds up well but can still be scratched by harder stones and grit.
- Put jewelry on last, after makeup, perfume, and hairspray, especially with peridot
- Clean with a soft, barely damp cloth; skip ultrasonic and steam cleaners for peridot
- Store pieces separately in a soft pouch so harder stones can't scratch softer ones
- Remove birthstone jewelry before swimming, showering, or heavy housework
For more on keeping sterling silver bright between wears, see our sterling silver and moissanite care guide, or read our December birthstone guide if you're shopping for more than one birth month this year.
Frequently Asked Questions
What is the August birthstone and what does it mean?
August actually has three birthstones: peridot, spinel, and sardonyx. Peridot is a vivid yellow-green gem long associated with protection and good fortune, spinel is the newest addition to the list, recognized in 2016 after centuries of being mistaken for ruby, and sardonyx is a banded stone used since antiquity for carved seals and signet rings.
Why does August have three birthstones instead of one?
Birthstone lists have grown over time as different trade groups added stones. Sardonyx comes from the older, traditional list, peridot became the modern standard decades ago, and spinel was added in 2016 by the American Gem Trade Association and Jewelers of America once its distinct identity from ruby and sapphire was widely recognized.
Is spinel a real gemstone or just an imitation ruby?
Spinel is entirely its own mineral, not an imitation of anything. Historic confusion happened because fine red spinel and ruby can look similar to the eye, and famous stones once labeled as rubies — including the Black Prince's Ruby in the British Crown Jewels — later turned out to be spinel once gemological testing improved.
Can I wear a peridot ring every day?
You can, but it takes more care than a harder stone. Peridot sits at Mohs 6.5 to 7 and is sensitive to sudden temperature changes and harsh chemicals, so a ring worn daily is more exposed than a pendant or earrings would be. Many buyers choose peridot for necklaces for exactly this reason.
Can MYNSU make me a custom August birthstone piece?
Yes — we build made-to-order pieces with genuine peridot, spinel, or sardonyx accents, including initial pendants and designs made for a specific milestone. Our ready-to-wear collection is moissanite and 925 sterling silver rather than birthstones, so for a true birthstone piece, start a custom design inquiry and tell us what you have in mind.
Every MYNSU order ships free within the US, backed by 30-day returns, and ships from our Irvine, California warehouse.