August birthstones: peridot, spinel, sardonyx
August added spinel to its birthstone list in 2016, making it one of three options alongside peridot (the modern standard) and sardonyx (the traditional, now-niche choice). Each suits a different style.
The three options
| Hardness | Color | Best for | |
|---|---|---|---|
| Peridot | 6.75 | Yellow-green to olive | The mainstream pick. Distinctive color, affordable, easy to find. See the peridot guide for origin and care. |
| Spinel | 8 | Every color — most often red, pink, or cobalt blue | The connoisseur's pick. Harder, usually untreated, and rarer than peridot for similar prices. |
| Sardonyx | 6.5 | Banded brown, white, and red chalcedony | The historical stone. Cameos, intaglios, and carved seals. Not a typical modern faceted-gem birthstone. |
For a modern August birthstone gift, default to peridot or spinel. Sardonyx is a thoughtful pick for someone who loves antique cameo or intaglio jewelry — otherwise the other two stones are more lifestyle- compatible.
See the deeper guides: peridot and spinel.
Browse peridots
Browse spinels
Browse sardonyx
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Written by
Anna
Jeweler · Formi Jewelry
Anna works with Formi clients on stone selection, setting design, and fit — making sure every piece is right before it’s made.
Book a consultation with our in-house jewelersLast updated May 2026