August Birthstone: Peridot, Spinel & Sardonyx — Full Guide

By Tolga Kavut, founder of Glamour Jewelry House · Updated September 2026

The August birthstone is peridot — a sunny yellow-green gem with two unusual claims to fame. It is one of only a handful of gemstones that occurs in exactly one color, and it is one of the very few born in volcanoes, formed in the earth’s upper mantle and thrown to the surface by eruptions. Some peridot didn’t even come from Earth: gem-quality crystals have been found inside meteorites.

August also has two more official birthstones — spinel, added in 2016 and the newest stone on the entire birthstone calendar, and sardonyx, the ancient banded stone August has claimed since antiquity. Here is all three, with the practical part first.

Shop August birthstone jewelrySee all 12 birthstones

August birthstones at a glance

What color is the August birthstone?

Peridot is olive green with a distinct yellow warmth — think early autumn light through leaves. It is one of the only gems that never occurs in another color, because the green isn’t an impurity: it’s the iron in the mineral itself. What varies is the shade, from a lemony lime in small stones to a deep, oily bottle green in larger ones, and the richest color usually comes from stones over three carats.

Peridot is also doubly refractive to an unusual degree, which is why fine stones have a velvety, almost slippery glow that photographs poorly and looks superb in person. If you have only seen the August birthstone in pictures, you have not really seen it.

What does the August birthstone mean?

Peridot is the stone of light. The Egyptians mined it on the forbidding island of Zabargad in the Red Sea, working at night because they believed the stones were invisible in daylight and glowed after dark; they called peridot the gem of the sun. Everywhere it traveled it kept that association — warding off nightmares and darkness, bringing good fortune and clear-headed strength. For a stone that forms in fire and darkness underground, “light out of darkness” is an unusually honest symbolism.

Spinel, August’s newest stone, brings its own meaning: revitalization and hope, fitting for a gem that spent centuries being mistaken for something else. Sardonyx, the oldest, was a Roman soldier’s stone, carved with the god Mars and worn for courage.

Spinel: the great impostor, finally recognized

For most of history, spinel had no reputation of its own — because the finest red spinels were sold as rubies. The Black Prince’s Ruby in the British Imperial State Crown and the “Timur Ruby” are both spinel; nobody knew until modern gemology could tell them apart. Spinel is genuinely excellent in its own right: 8 on the Mohs scale, brilliant, usually untreated, and available in reds, hot pinks, cobalt blues and violets. Its 2016 addition to August is the most recent change to the birthstone list, and one of the best-deserved.

How to buy a good peridot

Look for green, not yellow-brown. The most valuable peridot leans pure green; brownish stones are common and much cheaper. Compare two side by side and the difference is obvious.

Size buys saturation. Because color deepens with size, a 6–8 mm peridot shows the stone at its best. Happily, peridot is affordable enough that going bigger rarely hurts.

Untreated is the norm. Like garnet, peridot is almost never enhanced — another honest, natural stone at a friendly price.

Caring for peridot jewelry

At 6.5–7 Mohs peridot is moderately durable but sensitive to sudden temperature changes and acids. Warm soapy water only — no ultrasonic cleaners, no steam. It suits pendants and earrings better than knock-around rings.

Shop August birthstone jewelry

Every piece is made to order in 18K gold — choose peridot at checkout for an August birthday, and add a name, initial or date if you’d like it engraved.

Natural Birthstone NecklaceFrom $57 Birthstone RingFrom $57 Teardrop Birthstone NecklaceFrom $58 Family Birthstone NecklaceFrom $59 Personalized Birthstone BraceletFrom $59 Custom Name Necklace with BirthstoneFrom $59

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August birthstone jewelry: where to start

Peridot’s green is unusual in jewelry — warmer than emerald, brighter than jade — and it looks its best in yellow gold, where the two warm tones amplify each other.

Because peridot is a touch softer than the corundum months, a bezel-set August birthstone necklace is my standard recommendation: protected girdle, everyday wearability, and the stone catches sunlight beautifully at the collarbone. A low-set August birthstone ring works well for regular (not rough) wear. And in a family birthstone necklace or personalized birthstone bracelet, an August stone is the burst of lime that lifts the whole palette.

August birthstone questions

What is August’s birthstone?

Peridot is the modern favorite. August officially has three: peridot, spinel (added in 2016) and sardonyx.

What color is the August birthstone?

Peridot is yellow-green olive — one of very few gems that occurs in only one color. Spinel comes in red, pink, blue and violet; sardonyx is banded red-brown and white.

Why does August have three birthstones?

Sardonyx is the ancient stone, peridot the modern standard, and spinel was added by the American jewelry trade in 2016 — the newest addition to the entire birthstone list.

Is peridot from space?

Some of it, remarkably, is — gem-quality peridot has been found in pallasite meteorites. Most commercial peridot comes from volcanic rock, including large deposits in Arizona.

Is peridot durable enough for daily wear?

At 6.5–7 Mohs it is fine for necklaces, earrings and careful ring wear, but it dislikes ultrasonic cleaners, steam and sudden temperature changes.

Birthstones for every month

Each month has its own guide to its stone, color and meaning — or start with the complete birthstones by month chart.

• January birthstoneGarnet · Deep red
• February birthstoneAmethyst · Violet purple
• March birthstoneAquamarine · Sea blue
• April birthstoneDiamond · Colorless
• May birthstoneEmerald · Vivid green
• June birthstonePearl · Cream white
• July birthstoneRuby · Rich red
• August birthstonePeridot · Olive green
• September birthstoneSapphire · Royal blue
• October birthstoneOpal · Play-of-color
• November birthstoneTopaz · Golden yellow
• December birthstoneTurquoise · Robin’s-egg blue

You might also like

• May birthstone — emerald, the other great green birthstone
• July birthstone — ruby, the stone spinel was mistaken for
• October birthstone — opal and tourmaline, October’s pair