August Birthstone

Explore August's birthstones: peridot, spinel, and sardonyx — with mineral facts, history, symbolism, care tips, and gift ideas for August birthdays.

Peridot

Primary

Olivine — (Mg,Fe)₂SiO₄

Peridot is the gem-quality variety of the mineral olivine, a magnesium iron silicate. Its distinctive olive-green to yellow-green color comes from iron that is part of the crystal's chemical structure — not a trace impurity. At Mohs 6.5–7, it is suitable for most jewelry types when set carefully. Notably, peridot is one of the few gemstones that forms only in one color family. The largest gem-quality crystals come from Pakistan's Kohistan region; the U.S. state of Arizona (San Carlos Apache reservation) is the world's largest single producer by volume.

Hardness 6.5 – 7 / 10
Color Olive-green to yellow-green

Spinel

Modern (2016)

Spinel — MgAl₂O₄

Spinel is a magnesium aluminum oxide that occurs in a remarkably wide range of colors — red, pink, blue, violet, orange, and black — depending on trace element substitutions in its crystal structure. At Mohs 8, it is harder and more durable than peridot and nearly as hard as corundum. Spinel was officially added as an August birthstone in 2016. Historically, many of the world's most famous "rubies" — including the Black Prince's Ruby in England's Imperial State Crown — are actually red spinel, only identified through modern gemological analysis.

Hardness 8 / 10
Color Red, pink, blue, violet, orange

Sardonyx

Traditional

Chalcedony — SiO₂ (banded sard + onyx)

Sardonyx is a variety of onyx characterized by alternating bands of sard (reddish-brown chalcedony) and white or black onyx layers. Both sard and onyx are microcrystalline varieties of quartz (SiO₂). At Mohs 6.5–7, sardonyx is durable enough for most jewelry types. Its bold banding pattern makes it especially prized for cameos and intaglio carvings. It has been used in jewelry and seals since at least 4,000 BC in ancient Mesopotamia and was widely traded throughout the ancient world.

Hardness 6.5 – 7 / 10
Color Reddish-brown and white bands

Peridot — Key Facts

Mineral Family
Olivine ((Mg,Fe)₂SiO₄)
Peridot belongs to the olivine mineral group. It is a nesosilicate — a silicate where isolated SiO4 tetrahedra are bonded by magnesium and iron cations. The ratio of magnesium to iron determines both the exact color and some physical properties. Higher iron content shifts the color toward yellow-green and increases density.
Color Range
Olive-green to yellow-green
Peridot ranges from a pale yellowish-green to a rich, deep olive-green. The most prized shade is a pure, vivid "lime" or "grass" green with minimal yellow. Iron content determines the depth and hue: low iron produces lighter, more yellow stones; higher iron yields deeper, more saturated greens. Unlike most gemstones, peridot cannot occur in any other color family.
Mohs Hardness
6.5 – 7 / 10
Peridot's Mohs hardness of 6.5–7 places it in a durable but not extremely hard category. It is appropriate for pendants, earrings, and occasional-wear rings. For daily-wear rings, a bezel setting offers the best protection. Because quartz dust (Mohs 7) is common, peridot surfaces can be abraded by everyday particles — clean gently and store in a pouch.
Extraterrestrial Origins
Found in pallasite meteorites
Peridot is one of the few gems with confirmed extraterrestrial occurrences. Crystals of olivine (fayalite and forsterite) are embedded in pallasite meteorites — stony-iron meteorites formed at the core-mantle boundary of ancient planetesimals. Meteoritic peridot crystals are generally small but are scientifically significant as tangible pieces of the early solar system.
Primary Sources
Arizona (USA), Pakistan, Egypt
Arizona's San Carlos Apache reservation is the world's largest single source of peridot by volume, producing smaller crystals used primarily in beaded and commercial jewelry. Pakistan's Kohistan region yields the largest high-quality gem crystals, prized by collectors. Egypt's St. John's Island (Zabargad) in the Red Sea was the world's primary source for over 3,500 years of history; it is largely depleted today. Other sources include Myanmar, Vietnam, China, and Tanzania.
Birthstone Since
1912 (modern list)
Peridot was designated the August birthstone in 1912 by the American National Retail Jewelers Association's first standardized birthstone list. In ancient and medieval Europe, peridot was sometimes called "chrysolite" — a term that also applied to other yellowish-green gems, causing some historical confusion about which stone was meant in older texts.

Spinel — Key Facts

Mineral Family
Spinel group (MgAl₂O₄)
Spinel is a magnesium aluminum oxide belonging to the spinel mineral group. It forms isometric (cubic) crystals, typically as octahedra. Unlike corundum (which forms hexagonal crystals), spinel has a distinctly different crystal structure — yet it can produce red stones so similar to ruby in appearance that the two were indistinguishable without modern mineralogical testing.
Color Range
Red, pink, blue, violet, orange, black
Spinel is available in almost every color. Red and pink spinel are colored by chromium (the same element that colors ruby red). Blue spinel gets its color from iron and cobalt. Violet and lavender spinels contain manganese. Colorless, black (pleonaste), and orange (often called "flame spinel") varieties also exist. This wide palette makes spinel one of the most versatile colored gemstones.
Mohs Hardness
8 / 10
At Mohs 8, spinel is harder than peridot and sardonyx, and harder than most popular gems including topaz (8), aquamarine (7.5–8), and tourmaline (7–7.5). Only corundum (ruby, sapphire at Mohs 9) and diamond (Mohs 10) are significantly harder. This makes spinel an excellent choice for all types of jewelry, including daily-wear rings.
Famous Misidentifications
Black Prince's Ruby; Timur Ruby
The 170-carat "Black Prince's Ruby" set in England's Imperial State Crown and the 361-carat "Timur Ruby" in the British Royal Collection are both red spinels, not rubies. For centuries, gem traders in Central and South Asia could not reliably distinguish between ruby and spinel — both were mined in the same gem gravels and both were called "balas ruby" in the medieval gem trade.
Primary Sources
Myanmar, Sri Lanka, Tanzania, Tajikistan
Myanmar's Mogok Stone Tract is historically the most celebrated source of fine red and pink spinel, occurring in the same gem gravels as Myanmar's famous rubies. Sri Lanka produces a wide range of colors. Tanzania's Mahenge region yields vivid neon pink and red spinels. Tajikistan's Kuh-i-Lal mine supplied many of the historic spinels in royal treasuries. Vietnam is an emerging source of fine blue and violet spinel.
Added to Birthstone List
2016 (AGTA / Jewelers of America)
Spinel was added to the official August birthstone list in 2016 by the American Gem Trade Association and Jewelers of America — the first update to the modern birthstone list since the addition of tanzanite for December in 2002. The addition was partly driven by collector demand and by the gem trade's desire to bring awareness to spinel's long-overlooked status as a world-class gemstone.

Mohs Hardness Comparison

How the three August birthstones rank against common gemstones on the Mohs scale.

Diamond
10
Ruby / Sapphire (Corundum)
9
Spinel (August)
8
Aquamarine (Beryl)
7.75
Peridot (August)
6.75
Sardonyx (August)
6.75
Feldspar / Moonstone
6
Glass
5.5

The Mohs scale is ordinal — equal steps do not represent equal differences in absolute hardness. Diamond is approximately 4× harder than corundum (Mohs 9) in absolute terms. Peridot and sardonyx are shown at 6.75 as the midpoint of their 6.5–7 range.

History & Symbolism

Peridot

Ancient Egypt — "Gem of the Sun"
Peridot's earliest documented use comes from ancient Egypt. The Egyptians mined peridot on St. John's Island (Zabargad) in the Red Sea — one of the oldest known gem mines in the world, active as far back as 1500 BC. Egyptians called peridot "the gem of the sun" and believed it protected its wearer from night terrors and evil spirits. Some historians believe that Cleopatra's famous collection of "emeralds" may have actually been peridot from Zabargad, as the two stones were confused throughout antiquity.
Ancient Rome and the "Evening Emerald"
Roman naturalist Pliny the Elder described peridot as "topazion" in his first-century AD work "Naturalis Historia." Romans appreciated that peridot glows brilliantly under artificial light — oil lamps enhanced its color rather than dulling it, unlike many other gems. This quality earned it the nickname "evening emerald." Roman soldiers and senators wore peridot amulets for courage in battle and wisdom in political life.
Medieval Europe and Church Treasuries
Peridot was carried to Central Europe by the Crusaders, who brought stones looted from or purchased in the Middle East. Many large peridot stones were set into medieval church treasuries, reliquaries, and bishops' rings. The famous "Three Holy Kings" reliquary in Cologne Cathedral contains 200-carat peridots that were long believed to be emeralds until modern gemological testing. Peridot was associated with healing, lightness, and banishing evil.
Modern Era
Today peridot enjoys steady popularity as an affordable, vivid green gemstone. Pakistan's Kohistan region, discovered as a major source in the 1990s, supplies the finest large crystals with deep, saturated green color. Lab-grown peridot is not commercially significant — the stone is abundant enough in nature that synthetic production is not economically worthwhile. Peridot is the official state gem of Hawaii, where it forms in the island's volcanic basalt flows.

Spinel

Ancient Trade Routes and Royal Collections
Spinel has been mined and traded for at least 2,000 years, primarily from the gem-rich gravel deposits of Myanmar's Mogok Valley and Badakhshan province in modern-day Tajikistan/Afghanistan. The Badakhshan mines supplied spinels to Persian, Mughal, and Ottoman courts for centuries. The most prized red spinels were called "balas rubies" — a term derived from "Balascia," the medieval name for Badakhshan.
The Mughal Empire and the "Great Table"
The Mughal emperors were enthusiastic collectors of spinel. The "Timur Ruby" — a 361-carat red spinel now in the British Royal Collection — bears the engraved names of six Mughal rulers who owned it before it came to England. Mughal craftsmen engraved their names and dates directly onto large spinels to establish provenance, a practice unique to this gemstone. Many of these inscribed spinels survive today and are traceable through centuries of documented ownership.
European Crown Jewels and the Misidentification Era
Before the development of modern mineralogy in the 19th century, there was no reliable way to distinguish between ruby, red spinel, and red garnet without chemical analysis. The 170-carat "Black Prince's Ruby" in England's Imperial State Crown, the "Côte de Bretagne Ruby" (now known to be a red spinel, carved into the shape of a dragon) in the French crown jewels, and numerous other famous "rubies" in European treasuries were subsequently identified as spinel. These misidentifications persisted for centuries.
Recognition and the 2016 Birthstone Addition
For much of the 20th century, spinel suffered from being labeled "the great imposter" — its identity as the gem hidden behind famous rubies diminished its own reputation. Gradually, gemologists and collectors recognized spinel's unique qualities: its single-refractive optical properties (unlike corundum's double refraction), its natural inclusion-free crystals, and its extraordinary color range. In 2016, the American Gem Trade Association elevated spinel to official birthstone status for August, marking a new era for the stone.

Sardonyx

Ancient Mesopotamia and Egypt
Sardonyx is one of the oldest gemstones in continuous use. Beads and amulets carved from sardonyx have been found in Mesopotamian burial sites dating to approximately 4,000 BC. Ancient Egyptians used sardonyx in scarabs, seals, and funerary jewelry. Its distinctive layered banding made it ideal for carving multi-layered cameos where the white layer forms the raised figure against the darker ground.
Ancient Greece and Rome
Sardonyx reached peak popularity in ancient Greece and Rome. Roman soldiers wore sardonyx amulets engraved with images of Mars, the god of war, believing the stone instilled courage and brought victory in battle. Roman general and statesman Marcus Aurelius reportedly used a sardonyx signet ring to seal official documents. Roman craftsmen produced elaborate cameo portraits of emperors and mythological scenes in sardonyx, many of which survive in museum collections today.
Renaissance and European Courts
During the European Renaissance, sardonyx experienced a revival in prestige. The stone's layered structure enabled master gem carvers to create detailed portraits and allegorical scenes with natural white-on-brown color contrast. Portrait cameos of rulers and members of the nobility were highly fashionable gifts. Queen Elizabeth I of England received numerous sardonyx cameos as diplomatic gifts and wore them in portrait miniatures.
Modern Role as Traditional August Birthstone
In the modern era, sardonyx has a quieter presence than peridot and spinel in commercial jewelry. However, it remains the original, traditional August birthstone and retains significance in antique and vintage jewelry, cameo collecting, and seal engraving. Affordably priced and widely available, sardonyx offers the warmth of its reddish-brown banding at a fraction of the cost of the precious August birthstones.

Care Tips

Peridot

Warm soap and water only
Clean peridot with warm water, a soft brush, and mild dish soap. Rinse thoroughly. Never use ultrasonic or steam cleaners — peridot is sensitive to rapid temperature changes and strong vibrations that can expand internal fractures.
Avoid acids and household chemicals
Peridot is susceptible to attack by even mild acids. Keep it away from vinegar, citrus juices, sweat, and cleaning products containing acids or chlorine. Remove peridot jewelry before swimming or cleaning.
Store in a padded, separate pouch
Peridot (Mohs 6.5–7) can be scratched by harder gems. Store it separately, wrapped in a soft cloth or in a fabric-lined compartment, away from diamond, sapphire, ruby, spinel, and topaz.

Spinel

Mild soap, water, and soft brush
Clean spinel with warm soapy water and a soft toothbrush. Untreated spinel (most natural spinel on the market is untreated) can generally tolerate ultrasonic cleaning, but check with your jeweler if the stone's treatment status is uncertain.
Durable enough for everyday wear
At Mohs 8, spinel withstands daily wear better than peridot or sardonyx. It can be set in rings without the need for protective bezels, though prong settings remain perfectly appropriate. Spinel does not have cleavage planes, so it resists chipping better than many gems.
Store away from corundum and diamond
While spinel is hard, ruby and sapphire (Mohs 9) and diamond (Mohs 10) can still scratch it. Store spinel in a separate compartment or soft pouch away from these harder stones.

Sardonyx

Use mild soap and a soft cloth
Wipe sardonyx with a damp cloth and mild soap. A soft toothbrush can clean around carved cameo detail. Rinse well and dry with a lint-free cloth. Avoid harsh chemicals that can dull the polished surface.
Avoid ultrasonic cleaners
Chalcedony stones, including sardonyx, may have natural micro-fractures that ultrasonic vibrations can worsen over time. Hand cleaning is always the safer choice for any chalcedony-group stone.
Protect carved cameos from abrasion
Cameo surfaces have relief detail with thin raised areas that can chip if knocked against hard surfaces. Store cameo pieces flat, wrapped in soft cloth, and avoid wearing cameo brooches or rings in activities that risk direct impact.

Gift Ideas for August Birthdays

Peridot Solitaire Ring Peridot
An oval or cushion-cut peridot in yellow gold brings out the stone's warm olive-green color beautifully. Look for Pakistani origin stones for the deepest, most saturated green with minimum yellow cast.
Peridot and Diamond Pendant Peridot
A bezel-set round or pear-shaped peridot surrounded by a small diamond halo on a delicate gold chain is a classic, wearable gift that complements any skin tone.
Red or Pink Spinel Ring Spinel
A vibrant red or neon-pink Mahenge spinel set in white gold or platinum delivers extraordinary color impact — similar in appearance to ruby at a lower cost, with the added conversation piece of its history as "the great imposter" of royal jewels.
Blue or Lavender Spinel Earrings Spinel
Blue and lavender spinels are less commonly known and offer a sophisticated alternative to blue sapphire or tanzanite earrings. Cobalt blue spinel from Vietnam and Tanzania is particularly prized by collectors.
Sardonyx Cameo Brooch Sardonyx
A hand-carved sardonyx cameo brooch — featuring a classical profile portrait or floral motif — is a timeless heirloom gift with centuries of tradition behind it. Antique and vintage examples are widely available.
August Birthstone Stacking Set All three
A trio of thin stacking rings featuring peridot, spinel, and sardonyx cabochons gives the August birthday person all three official birthstones in one elegant layered look.

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Summary

Explore August's birthstones: peridot, spinel, and sardonyx — with mineral facts, history, symbolism, care tips, and gift ideas for August birthdays.

How it works

  1. August's primary modern birthstone is peridot (recognized since 1912).
  2. Spinel was added as the third official August birthstone in 2016 by the American Gem Trade Association.
  3. Sardonyx is the original traditional birthstone for August, used in jewelry for thousands of years.
  4. Browse the hero cards to compare peridot, spinel, and sardonyx at a glance.
  5. Explore the Key Facts grids for mineral family, color, hardness, and origin details.
  6. Read the History and Symbolism section to understand the cultural legacy of each stone.
  7. Check Care Tips to keep your August birthstone jewelry in top condition.
  8. Use the month selector at the bottom to look up birthstones for any other month.

Use cases

  • Find a meaningful birthstone gift for an August birthday.
  • Understand why August has three birthstones and how they differ.
  • Learn the historical connection between spinel and famous misidentified crown jewels.
  • Discover the unique extraterrestrial origin story of some peridot deposits.
  • Care for peridot, spinel, or sardonyx jewelry to preserve its beauty.
  • Explore affordable August birthstone alternatives for any budget.
  • Plan an August-themed birthstone jewelry collection.
  • Look up birthstones for any month using the interactive month selector.

Frequently Asked Questions

Last updated: 2026-06-10 · Reviewed by Nham Vu