August Birthstone: Peridot, Spinel & Sardonyx
August is one of only three months with a trio of birthstones: lime-green peridot, banded sardonyx, and spinel, which the jewellery trade added in 2016. Here's what each stone is, how it wears, and what makes a good gift.
Key Takeaways
- August has three birthstones: peridot (the modern classic), sardonyx (the original traditional stone), and spinel (added in 2016).
- Spinel became an official August birthstone in 2016, joining peridot โ one of the few changes to the list since the modern set was first agreed in the early twentieth century, per the American Gem Society.
- Peridot is a yellowish-green gem, about 6.5 to 7 on the Mohs hardness scale, so it wears fine in earrings and pendants but needs a protective setting in a daily ring (GIA).
- Spinel is harder, around 8 on the Mohs scale, comes in red, pink, blue and more, and was famously mistaken for ruby in royal jewels for centuries (GIA).
- For an everyday ring, spinel is the tougher pick; for a green-stone gift on a budget, peridot is hard to beat.
What is the August birthstone?
August has three birthstones: peridot, sardonyx, and spinel. Most jewellers treat peridot as the main one โ it's the green stone you'll see in nearly every "August" piece โ while sardonyx is the older traditional choice and spinel is the newest. The Gemological Institute of America lists all three for the month, so you can pick whichever suits the person and the piece.
If you only remember one, remember peridot. If you want something a bit different, spinel gives you red, pink, and blue options that most people don't realise are an August stone at all.
Peridot: the classic green stone
Peridot is the gem form of the mineral olivine, and it's one of the few gemstones that comes in only one basic colour โ green, ranging from a soft yellowish-green to a vivid lime. The GIA notes it's been mined for thousands of years, including on Zabargad Island in the Red Sea off Egypt; today a lot of it comes from Pakistan, Myanmar, and the San Carlos Reservation in Arizona.
People have long tied peridot to good fortune, calm, and protection โ the ancient Egyptians prized it as a sun-coloured gem. On the practical side, peridot sits around 6.5 to 7 on the Mohs hardness scale, which is softer than sapphire or spinel. That makes it lovely in earrings, pendants, and dress rings, but for a ring worn every day I'd steer you toward a bezel or otherwise protected setting so the edges don't chip. If you want a deeper comparison of how different stones hold up, our Full Gemstone Guide walks through hardness and wear for the common gems.
Sardonyx: the traditional birthstone
Before peridot took over, sardonyx was the original August stone. It's a banded form of chalcedony quartz โ reddish-brown and white layers running in straight stripes, which is exactly what made it prized for carved cameos and signet rings in the ancient world. Roman soldiers wore sardonyx carved with figures of heroes, believing it gave courage.
You'll see sardonyx less often in modern shops because it's an opaque, banded stone rather than a sparkly faceted one, but it's a great pick for a man's signet ring or a vintage-style piece. It's a quartz, so it's reasonably hard and wears well day to day.
Spinel: the 2016 addition
Spinel is the newest August birthstone. It was added in 2016 alongside peridot โ one of the rare changes to the official list, which doesn't move often, according to the American Gem Society. That's a big deal in our trade.
The reason spinel earned its spot is partly its history. For centuries, big red spinels were mistaken for rubies โ the famous "Black Prince's Ruby" set in the British Imperial State Crown is actually a spinel, and so is the "Timur Ruby." The GIA explains that spinel comes in a wide range of colours: red, hot pink, purple, blue, and more. It's also a tough, single-crystal stone at about 8 on the Mohs scale, harder than peridot and a genuinely practical choice for a ring you wear daily.
One honest note from our bench: fine natural red and "cobalt" blue spinel can cost as much as or more than many sapphires, because the best material is rare. Pink and purple spinels are more affordable and make beautiful, durable everyday rings.
August birthstones compared
| Stone | Role | Colour | Mohs hardness | Best for |
|---|---|---|---|---|
| Peridot | Modern classic | Yellowish to lime green | 6.5โ7 | Earrings, pendants, protected rings |
| Sardonyx | Traditional / original | Reddish-brown & white bands | ~6.5โ7 (quartz) | Cameos, signet rings, vintage styles |
| Spinel | Added 2016 | Red, pink, blue, purple | ~8 | Everyday rings, statement pieces |
Hardness figures for peridot and spinel are from the GIA.
Choosing an August birthstone gift
For a first piece or a gift on a sensible budget, peridot in a pendant or pair of studs is a safe, cheerful choice โ the green reads as fresh and summery, which suits an August baby. For something more unexpected, a pink or purple spinel ring gives you durability for daily wear and a colour most people can't name on sight, which tends to start a conversation. For a man, a sardonyx signet is a quiet nod to the traditional stone.
We design and set August birthstones in-house on our Coquitlam bench, so if you have a stone you love but the wrong setting, our on-site goldsmith can rework it rather than starting from scratch. If you're shopping across the calendar, our parent guide, Birthstones by Month: Modern & Traditional Stones, covers every month, and you can compare neighbouring stones like January's garnet, February's amethyst, and March's aquamarine.
Frequently Asked Questions
What is the birthstone for August?
August has three birthstones: peridot, sardonyx, and spinel. Peridot is the modern go-to green stone, sardonyx is the original traditional stone, and spinel was added to the official list in 2016.
When was spinel added as an August birthstone?
Spinel was added in 2016, joining peridot as a second modern August stone. It was one of the rare changes to the official birthstone list, which the jewellery trade doesn't update often.
Is peridot a good stone for an everyday ring?
Peridot is on the softer side at about 6.5 to 7 on the Mohs scale, so it's better suited to earrings and pendants. If you want it in a daily ring, ask for a bezel or protective setting so the edges don't chip over time.
Why was spinel mistaken for ruby?
Red spinel and ruby look very similar and are often found in the same deposits. For centuries jewellers couldn't tell them apart, so famous "rubies" such as the Black Prince's Ruby in the British Imperial State Crown turned out to be spinels.
Which August birthstone is the most durable?
Spinel, at around 8 on the Mohs scale, is the hardest and toughest of the three, which makes it the most practical for a ring worn every day. Peridot and sardonyx are softer and better suited to gentler wear.
What does peridot symbolise?
Peridot has long been linked to good fortune, calm, and protection. The ancient Egyptians prized it as a sun-coloured gem, and it's also the traditional gift for a 15th wedding anniversary.