August's birthstones are yellowish green peridot and spinel in red, pink, blue and more, with banded sardonyx as the original 1912 stone.
August has the most layered history on the American list. In 1912 sardonyx was the primary stone and peridot the alternate. Over time peridot took the lead, and in 2016 Jewelers of America and the American Gem Trade Association added spinel, making August the third month with three stones after June and December. Sardonyx has since dropped off the Jewelers of America list, though the American Gem Society still names it as the original August birthstone.
Peridot's name is traced to the Arabic faridat, meaning gem, and for centuries it served as a talisman against evil spirits and the terrors of the night. Spinel takes its name from the Latin spina, thorn; famous red spinels, such as the Black Prince's Ruby in the British crown, were long mistaken for rubies. Sardonyx was a Roman favorite for seals and cameos, and Roman soldiers wore sardonyx rings engraved with Mars.
Peridot is the gem variety of olivine, and it stays within one color family: yellowish green to greenish yellow. It measures 6.5–7 on the Mohs scale. Notable sources include China, Myanmar, Pakistan, Tanzania, Vietnam and the United States, while the island of Zabargad in Egypt was a historic source. Peridot is sensitive to sudden temperature changes and to acids, which shapes how it should be cleaned.
Spinel is its own mineral species, and its palette is broad: red, pink, orange, purple, violet and blue. At 8 on the Mohs scale it is hard and durable. Tajikistan, Myanmar, Sri Lanka, Vietnam, Tanzania and Pakistan are notable sources. Red spinel can look so much like ruby that the two were confused for centuries. It became an August birthstone in 2016 and is the traditional 22nd-anniversary gem.
Sardonyx is a banded chalcedony that layers sard with onyx. Its stripes are typically reddish brown and white, or brown and black, which made it ideal for carving cameos and seals that show a design against a contrasting layer. Hardness falls at 6.5–7. Notable sources include India, Brazil, Germany, the Czech Republic, Madagascar, Uruguay and the United States. Many pieces are dyed.
Peridot is the most temperamental of the three: never use steam or ultrasonic cleaners, wash it with mild soap and a soft brush, and keep it away from acids and harder gems. Spinel is durable, and ultrasonic or steam cleaning is fine unless the stone is fractured, though high heat can fade some colors. Sardonyx is often dyed, so warm soapy water is the safest choice and high heat should be avoided.
| US list | UK list | Japanese list (2021) |
|---|---|---|
| PeridotSpinel(Sardonyx) | Peridot(Spinel) | PeridotSardonyxSpinel |
Sardonyx was the 1912 choice and peridot its alternate. Peridot later moved up, spinel was added in 2016, and the American Gem Society kept sardonyx as an alternative, leaving three options. Jewelers of America lists peridot and spinel.
Close, but not identical. The National Association of Jewellers names peridot first and spinel as the alternative, with no mention of sardonyx. An earlier UK chart from the National Association of Goldsmiths listed sardonyx as the alternative instead.
JanuaryGarnet
FebruaryAmethyst
MarchAquamarine
AprilDiamond
MayEmerald
JunePearlMoonstoneAlexandrite
JulyRuby
AugustPeridotSpinel
SeptemberSapphire
OctoberOpalTourmaline
NovemberTopazCitrine
DecemberTurquoiseTanzaniteZirconBirthstones are a jewelry and cultural tradition, and their meanings are folklore. Gem facts are compiled from public material by GIA, the American Gem Society and Jewelers of America.