Sardonyx is the traditional birthstone for August, holding that position in medieval, early modern, and traditional birthstone lists for at least seven hundred years. The 1912 birthstone standardisation by what became the American Gem Society included sardonyx as the August stone alongside peridot, with the two species offered as alternatives. The subsequent rise of peridot to commercial dominance during the twentieth century, and the formal addition of spinel to the August list by the Jewelers of America in 2016, have reduced sardonyx's contemporary retail visibility — but the traditional designation remains intact in heritage and traditional birthstone references, and sardonyx is a culturally and historically substantive choice for August birthdays and birthstone gifts.

Historical basis

Sardonyx's connection to August traces to several layered traditions. Medieval Christian gem symbolism associated sardonyx with the apostle Thaddaeus and with the eighth foundation stone of the New Jerusalem in Revelation 21:20, both of which contributed to the August attribution through patristic and ecclesiastical traditions. Astrological associations linked sardonyx variously to Leo and Virgo, the two zodiacal signs spanning August in the modern calendar. Pliny the Elder and other classical writers described sardonyx as a stone of strength, eloquence, and protection, traits the medieval and Renaissance traditions developed into the cluster of August symbolism that birthstone lists eventually formalised.

The 1912 standardisation and later additions

The American National Retail Jewelers Association meeting at Kansas City in 1912 produced the first widely adopted modern birthstone list. The August entry listed sardonyx and peridot as joint birthstones, reflecting the compromise between the long traditional sardonyx attribution and the rising commercial interest in peridot, which had become more widely available through Egyptian and St John's Island production. Subsequent revisions and the introduction of alternative-birthstone listings preserved sardonyx as the traditional option while elevating peridot to the modern primary.

In 2016, the Jewelers of America added spinel to the August list, recognising the species' growing collector profile and the marketing potential of three options for the month. Spinel's addition further diluted sardonyx's retail share but did not displace it from the traditional list. Buyers and gift-givers can choose any of the three depending on preference, budget, and the recipient's taste.

Practical considerations

Sardonyx offers durability appropriate for jewellery use — hardness 6.5 to 7 on the Mohs scale, sufficient for ring, pendant, and earring formats with reasonable care. The banded structure makes the material visually distinctive and supports cameo and intaglio work that is unavailable in single-coloured peridot or spinel. For recipients who appreciate cultural and historical depth, a sardonyx cameo or intaglio with classical or contemporary subject matter offers a gift with two layers of meaning — the August birthstone tradition and the broader sardonyx tradition stretching from Roman state cameos to the present.

In the trade

For August birthday and birthstone gifts, sardonyx is best presented as a heritage or traditional alternative to the more commercially familiar peridot and spinel. The price point for sardonyx is typically lower than for comparable-size peridot or spinel of fine quality, allowing the gift budget to support a more substantial piece — a worked cameo or intaglio rather than a faceted stone — at the same overall outlay. Antique and vintage cameos offer an additional dimension: pieces from the Victorian, Edwardian, or earlier periods carry both the birthstone designation and the decorative-arts pedigree, often within reasonable budgets compared to contemporary fine jewellery.

Bespoke cameo commissions remain possible through specialist workshops in Idar-Oberstein and Torre del Greco for clients who want a portrait, monogram, or specific symbolic motif rendered in sardonyx for a milestone August birthday. See also sardonyx, sardonyx cameo.

Further reading

• GIA — birthstones reference and history
• GIA — chalcedony reference
• International Gem Society — onyx and sardonyx reference
• AGTA — birthstones