2027 Forecast

August · Yellow-green

August birthstone: Peridot

The August birthstones are Peridot and Spinel — the month carries 2 official modern stones, which is why sources disagree about it. The traditional list names Sardonyx instead, and only 2 of the 12 months differ that way.

1912 jewelers’ list
Sardonyx or peridot · Kansas City
Older lists
Carnelian · 5 of 8 Kunz’s tally of 8 old lists
August births
8.91% #1 of 12 months, US 2000–2014

Kunz 1913; US births 2000–2014.

The months either side, and the same month in flowers: July birthstone, September birthstone and August birth flower.

All twelve months, modern and traditional lists in one table: birthstones by month.

August Birthstones: Peridot and Spinel
Modern birthstone Peridot, Spinel
Traditional birthstone Sardonyx
Color Yellow-green
Birth flower Gladiolus and Poppy
Zodiac signs Leo, Virgo
Hardness (Mohs) 6.5–7

Spinel was added in 2016, the most recent change to the modern list. The older lists favored carnelian — five of the eight George Kunz compared in 1913 — and sardonyx, three; the American list of 1912 made sardonyx the stone and peridot its alternative.

Note the split: Peridot is the modern choice, while Sardonyx held the month in the older list. Both are still considered correct, so if you were told a different stone growing up, that is probably why.

August stones in detail

Peridot

Composition Magnesium iron silicate ((Mg,Fe)₂SiO₄) — gem-quality olivine
Hardness · Crystal system 6.5–7 · Orthorhombic
Mined in Pakistan, Myanmar, USA (Arizona), China, Egypt

Peridot arrives on Earth in meteorites — pallasite meteorites carry gem-quality crystals formed beyond this planet.

Traditionally linked to lightness, release of resentment and fresh perspective.

Care. Soapy water only. Sensitive to acid and rapid temperature change, so no steam and no ultrasonic.

Spotting a fake. Green glass is the common fake. Peridot has unusually strong double refraction — look through it at a straight line and the line appears doubled.

Spinel

Composition Magnesium aluminum oxide (MgAl₂O₄)
Hardness · Crystal system 8 · Cubic
Mined in Myanmar, Tanzania, Sri Lanka, Vietnam, Tajikistan

Several famous "rubies" in the British Crown Jewels — including the Black Prince's Ruby — are spinel.

Traditionally associated with renewal and recovering energy after depletion.

Care. Warm soapy water. Durable and safe in ultrasonic.

Spotting a fake. Historically confused with ruby, and several crown rubies turned out to be spinel. Spinel is singly refractive and ruby is not, which settles it under a loupe.

Sardonyx

Composition Banded chalcedony — alternating layers of sard and onyx
Hardness · Crystal system 6.5–7 · Trigonal
Mined in India, Brazil, Germany, Czech Republic

Its parallel banding made it the preferred material for cameos — carvers cut through a pale layer to reveal a dark one beneath.

Traditionally linked to steadiness, discipline and durable commitments.

Care. Warm soapy water and a soft cloth. Avoid prolonged soaking.

Spotting a fake. Banded agate is often dyed to imitate sardonyx. Natural banding is irregular; dyed banding is too even and the color sits in the porous layers.

The story of the August stones

Peridot is one of the few gems formed deep in the Earth's mantle and carried up by volcanic activity. The ancient Egyptians gathered it on Zabargad, a small island in the Red Sea, and some of the "emeralds" in medieval church treasuries have since turned out to be peridot. Sardonyx, banded red-brown and white, was a favorite of Roman engravers for seals — hot wax was said not to stick to it.

Choosing an August stone

Peridot is the budget-friendly August choice, and it only comes in green, from lime to olive; the richest green with the least brown is the one to look for. Spinel offers reds, pinks and blues at a fraction of ruby or sapphire prices, and it is rarely treated. Sardonyx is the choice for a signet ring or an engraved seal rather than a faceted stone.

Primary source

August in George Kunz’s Curious Lore of Precious Stones (1913)

The verse for August
“Wear a carnelian or for thee No conjugal felicity; The August-born without this stone, ’Tis said, must live unloved, alone.”
Kunz on the 1912 list
“Another undesirable change takes the chrysolite (peridot) from the place it has always occupied as the gem of September, and makes of it an alternate for August, with the sardonyx, while the sapphire, properly the gem for April, is made the birth-stone for September.”
George Frederick Kunz, The Curious Lore of Precious Stones (Philadelphia and London: J. B. Lippincott, 1913), chapter IX, “Birth-Stones” — read the original text. Kunz’s traditional stone for August is carnelian, and the jewelers’ list adopted in Kansas City in 1912 gives sardonyx (alternative: peridot). In his tally of eight older lists, August went to carnelian in 5 of them, sardonyx in 3, moonstone in 1, topaz in 1, alexandrite in 1 — some lists give a month two stones. Which lists Kunz compared, and where the verses come from →

August birth flowers

Gladiolus

Traditionally signifies strength of character.

Poppy

Traditionally signifies remembrance and rest.

More on August birth flowers →

If you go by zodiac sign instead

August spans two signs — Leo and Virgo — and the zodiac stone list does not match the monthly one. Which applies to you depends on the day, not just the month.

Leo stones · Virgo stones

Questions about the August birthstone

What is the birthstone for August?

The modern August birthstones are Peridot and Spinel. The traditional stone is Sardonyx.

What color is the August birthstone?

Yellow-green.

What is the August birth flower?

Gladiolus and Poppy; the gladiolus traditionally signifies strength of character.

Is Peridot hard enough to wear every day?

Peridot rates 6.5–7 on the Mohs scale. It can be worn often, with care around acid and sudden changes of temperature.

What zodiac signs fall in August?

Leo and Virgo.

Other months

January February March April May June July September October November December

Measured against our reference of 43 stones

The August stones, by hardness

Peridot · modern Mohs 6.5–7 · +0.4 vs average · wear with care
Spinel · modern Mohs 8 · +1.65 vs average · everyday ring
Sardonyx · traditional Mohs 6.5–7 · +0.4 vs average · everyday ring
Average across all 43 stones Mohs 6.35
Modern and traditional different stones
August birthstones on the Mohs hardness scale
August birthstones on the Mohs hardness scaleMohs scale from talc (1) to diamond (10) with the August birthstones marked: Peridot 6.5–7, Spinel 8, Sardonyx 6.5–7 (traditional).Peridot: Mohs 6.5–7Peridot 6.5–7Spinel: Mohs 8Spinel 8Sardonyx: Mohs 6.5–7Sardonyx 6.5–7Garnet: Mohs 6.5–7.5Amethyst: Mohs 7Citrine: Mohs 7Rose Quartz: Mohs 7Clear Quartz: Mohs 7Smoky Quartz: Mohs 7Aquamarine: Mohs 7.5–8Emerald: Mohs 7.5–8Bloodstone: Mohs 6.5–7Peridot: Mohs 6.5–7Sardonyx: Mohs 6.5–7Zircon: Mohs 6–7.5Carnelian: Mohs 6.5–7Onyx: Mohs 6.5–7Agate: Mohs 6.5–7Tiger's Eye: Mohs 6.5–7Aventurine: Mohs 6.5–7Diamond: Mohs 10Pearl: Mohs 2.5–4.5Alexandrite: Mohs 8.5Moonstone: Mohs 6–6.5Labradorite: Mohs 6–6.5Pyrite: Mohs 6–6.5Ruby: Mohs 9Sapphire: Mohs 9Spinel: Mohs 8Topaz: Mohs 8Opal: Mohs 5.5–6.5Rhodonite: Mohs 5.5–6.5Tourmaline: Mohs 7–7.5Turquoise: Mohs 5–6Lapis Lazuli: Mohs 5–6Hematite: Mohs 5–6Tanzanite: Mohs 6–7Jade: Mohs 6–7Obsidian: Mohs 5–5.5Malachite: Mohs 3.5–4Amber: Mohs 2–2.5Selenite: Mohs 2Fluorite: Mohs 4Sodalite: Mohs 5.5–6Kyanite: Mohs 4.5–7Lepidolite: Mohs 2.5–31Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5window glass 5.5household dust (quartz) 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com
August birthstones on the Mohs hardness scaleMohs scale from talc (1) to diamond (10) with the August birthstones marked: Peridot 6.5–7, Spinel 8, Sardonyx 6.5–7 (traditional).Peridot: Mohs 6.5–7Peridot 6.5–7Spinel: Mohs 8Spinel 8Sardonyx: Mohs 6.5–7Sardonyx 6.5–71Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5glass 5.5dust 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com

August on the scale: Peridot 6.5–7, Spinel 8, Sardonyx 6.5–7 (traditional). Of the twelve months’ first-listed modern stones, Peridot is the 9th hardest.

Peridot: Magnesium iron silicate ((Mg,Fe)₂SiO₄) — gem-quality olivine. Crystal system Orthorhombic. Below Mohs 7 it is scratched by ordinary airborne dust — quartz sits at 7.

Who this month covers

Days in August 31
Leo · August 1–22 70.9% of August births
Virgo · August 23–31 29.1% of August births

August is mostly Leo territory: the sign claims 22 of its days, leaving Virgo the last 9, and in US births for 2000–2014 its share of the month was 70.9%. Exact sign dates →

Sources

  1. George Frederick Kunz, The Curious Lore of Precious Stones (Philadelphia and London: J. B. Lippincott, 1913), chapter IX, “Birth-Stones”

Statements of fact on this page were checked against these sources in October 2026. How we choose and check sources: editorial policy.

Cite this page

AstroHot. “August Birthstones: Peridot and Spinel.” Accessed October 28, 2026. https://astrohot.com/birthstones/by-month/august/

For Wikipedia {{cite web |title=August Birthstones: Peridot and Spinel |url=https://astrohot.com/birthstones/by-month/august/ |website=AstroHot |access-date=2026-10-28}}