August Birthstones: Peridot, Spinel, and Sardonyx – A Triad of Color and Meaning

Introduction

For those born in August, the birthstone tradition offers a rich and diverse selection of gemstones. While historically associated with peridot, modern revisions to the birthstone chart include spinel and sardonyx as additional options. These three gemstones each carry fascinating histories, distinct gemological properties, and varied cultural significances.

This article explores the birthstones of August in depth, drawing upon the most reliable and verified sources. Readers will gain insight into the geological origins, physical characteristics, historical uses, and metaphysical beliefs surrounding peridot, spinel, and sardonyx. Whether you are a jeweler, a gemstone collector, a student of geology, or simply curious about the magic of birthstones, this article provides a comprehensive and authoritative perspective on the August birthstone options.

History and Lore

Peridot: The Green Fire of the Ancients

Peridot has long been associated with August and is widely regarded as the classical August birthstone. Its history is as colorful as its green hue. The earliest known use of peridot dates back to ancient Egypt, where it was known as “the gem of the sun,” often used in amulets and protective jewelry. The Egyptians sourced peridot from a volcanic island in the Red Sea, now known as Zabargad Island.

Despite its terrestrial origins, some cultures believed peridot fell from the sky. Meteorites containing peridot have been found, contributing to the belief that the stone carried celestial power. In medieval Europe, peridot was sometimes mistaken for emeralds due to its similar green tones and was worn as an adornment by the aristocracy.

Peridot was also a popular gemstone in Roman times, particularly for cameos and intaglios. The gem's versatility and attractive color made it a favored choice for both men and women.

Spinel: The Noble Newcomer

Spinel is a relatively recent addition to the August birthstone lineup. In July 2016, the American Gem Trade Association (AGTA), in collaboration with the Jewelers of America (JA), officially recognized spinel as a birthstone for August. This decision followed a long-standing tradition of misclassification—some of the world’s most famous red gems, including the “Black Prince’s Ruby” in the British Crown Jewels, are actually spinels, not rubies.

Spinel's history as a gemstone can be traced back to the 18th century, where it was prized by royalty and collectors for its brilliance and clarity. Its striking red hue rivals that of fine rubies, and its blue varieties frequently resemble top-quality sapphires. The gem's addition to the August birthstone category significantly expands the color options for those celebrating their birthdays in this month.

Its newfound status as a birthstone is viewed as an opportunity to bring greater awareness and appreciation to spinel. The gem is not only beautiful but also practical for everyday wear—offering durability and a range of price points suitable for various budgets.

Sardonyx: The Layered Legacy

Sardonyx, a type of chalcedony, has been carved into cameos and intaglios for millennia. Though it is considered a birthstone for August, it lacks the vivid, eye-catching appeal of peridot and spinel. However, sardonyx has deep historical roots, particularly in the Roman Empire, where it was used extensively for cameos. These carvings often depicted mythological figures or were used for personal seals and engraved rings.

The stone is typically characterized by alternating bands of sard (a reddish-orange chalcedony) and onyx (black chalcedony), giving it a distinctive and elegant appearance. Though less prominent in modern jewelry than peridot or spinel, sardonyx has maintained a place in the world of carved stones due to its hardness and ease of carving.

Geological Formation and Sources

Peridot: Born from Volcanic Fire

Peridot is primarily composed of the mineral olivine, a magnesium iron silicate. It forms in the Earth's mantle under high pressure and temperature conditions and is brought to the surface by volcanic activity. The most common sources of peridot include basalt flows and volcanic rocks.

Significant deposits of peridot are found in a variety of regions, including:

United States (Arizona, Nevada): Peridot is mined in the U.S., particularly in areas like the San Carlos Apache Reservation in Arizona.
Zabargad Island (Red Sea): One of the most historically important sources, now known for its high-quality stones.
Sri Lanka: Known for producing vibrant green peridots.
Madagascar, Egypt, and China: Modern sources with varying levels of quality and availability.

Peridot is also found in meteorites—most notably in pallasite meteorites, where it occurs in conjunction with nickel-iron. These extraterrestrial deposits, while not typically used in jewelry, add to the gem’s mystique and its association with cosmic origins.

Spinel: A Hidden Treasure of the Earth

Spinel is a magnesium aluminum oxide (MgAl₂O₄) with a simple crystal structure that varies depending on its chemical composition. The gem's hardness is 8 on the Mohs scale, making it suitable for all types of jewelry, including rings and bracelets that experience daily wear.

Spinel is found in a range of geological environments, primarily in igneous and metamorphic rocks. Major sources include:

Sri Lanka: A key historical and modern source for high-quality red and blue spinels.
Myanmar (Burma): Produces some of the finest red spinel, with hues that rival ruby.
Vietnam and Thailand: Recent discoveries have shifted the mining focus to these regions.
Brazil and Afghanistan: Additional sources contributing to global availability.

Spinel’s inclusion in the birthstone chart for August is a reflection of its growing recognition in the gemstone trade and its increasing presence in both antique and modern jewelry.

Sardonyx: The Banded Beauty

Sardonyx is a form of chalcedony, a microcrystalline quartz, and is composed primarily of silicon dioxide. What sets sardonyx apart is its alternating bands of deep red and white (or black) colors, which form as the mineral is deposited in concentric layers within sedimentary or volcanic rocks.

The most historically significant sources of sardonyx include:

Turkey (Lydian onyx): Known for producing cameos during the Roman era.
Brazil: A modern and abundant source, particularly for sardonyx used in carvings and carved jewelry.
India, Uruguay, and the United States: Additional regions where sardonyx is mined for both carving and jewelry use.

The gem's relative softness (6.5–7.5 on the Mohs scale) allows for intricate carving, making it ideal for cameos and small figurines. Despite its lower profile in the modern market, sardonyx remains a valued medium among artists and collectors of antiques.

Gemological Properties

Peridot: Green Radiance from Olivine

Peridot is one of the few gemstones that occur in only one distinct color—green. The intensity of the green depends on the amount of iron in the stone. More iron results in a deeper, more saturated green.

Property	Value
Chemical Formula	(Mg,Fe)₂SiO₄
Crystal System	Orthorhombic
Mohs Hardness	6.5–7
Refractive Index	1.65–1.69
Specific Gravity	3.3–4.6
Color	Yellowish green to olive green
Color Cause	Iron impurities
Cleavage	Perfect in two directions
Typical Inclusions	Minor internal inclusions
Best Cut	Faceted for maximum reflection

Due to peridot’s perfect cleavage, it must be handled with care during cutting and setting to avoid damage.

Spinel: A Versatile and Durable Choice

Spinel is often admired for its versatility and strength. The gem’s range of colors—from deep red to vibrant blue and even colorless—reflects its chemical makeup, particularly the presence of chromium, iron, or cobalt.

Property	Value
Chemical Formula	MgAl₂O₄
Crystal System	Cubic
Mohs Hardness	8
Refractive Index	1.718–1.776
Specific Gravity	3.6–4.0
Color	Red, orange, blue, pink, purple, black
Color Cause	Chromium for red, cobalt for blue
Cleavage	No cleavage
Typical Inclusions	Rare; usually clean
Best Cut	Round brilliant or cabochon

Spinel’s lack of cleavage and high hardness make it an excellent choice for rings and everyday wear.

Sardonyx: The Carver's Favorite

Sardonyx belongs to the chalcedony family of silicate minerals and is noted for its fine-grained, microcrystalline structure.

Property	Value
Chemical Formula	SiO₂ (silicon dioxide)
Crystal System	Trigonal (quartz family)
Mohs Hardness	6.5–7.5
Refractive Index	1.53–1.54
Specific Gravity	2.60–2.64
Color	Reddish-brown, white or black bands
Color Cause	Iron oxides
Cleavage	No cleavage
Typical Inclusions	None to small, scattered
Best Cut	Cameo, intaglio or cabochon

Sardonyx is particularly popular in carved pieces because its layered structure enhances detail and contrast.

Symbolism and Metaphysical Beliefs

Peridot: The Stone of Light and Prosperity

Throughout history, peridot has been associated with positive energy. In ancient Egypt, it was believed to ward off nightmares and promote good fortune. Some tribes used peridot as a solar stone, believing it represented the light and warmth of the sun.

Modern metaphysical practitioners consider peridot a stone of transformation. It is often used in meditation, helping practitioners release negative emotions and welcome a sense of clarity and optimism. Peridot is associated with the heart chakra, aiding in love, healing, and emotional balance.

The gem also symbolizes renewal and growth. It is a popular choice for those embracing new beginnings, such as new careers, relationships, or personal goals.

Spinels: Gems of Passion and Protection

Each color of spinel is linked to its own set of meanings. Red spinel is often referred to as the “stone of vitality,” symbolizing strength, courage, and passion. Because it is frequently mistaken for ruby, it was historically thought to carry the same protective and romantic properties.

Blue spinel is associated with wisdom, serenity, and truth. Those who work with blue spinel may feel a greater sense of calm and focus, which is why it is a popular stone among students and professionals.

In general, spinel is believed to enhance self-esteem, encourage self-discovery, and provide a calming influence. It is thought to help the wearer align with their true desires and protect them from negative external influences.

Sardonyx: The Shield of Strength and Order

Sardonyx has had varied roles in metaphysical beliefs and mythology. In Roman times, it was considered a protective stone, especially when carved into cameos that depicted protective gods or personal shields. It was also worn as an amulet to ward off jealousy and envy.

Modern metaphysical practitioners see sardonyx as a grounding and balancing force. It is believed to help maintain order in the home and workplace. The stone is also associated with endurance and composure, helping individuals handle difficult or stressful situations with grace and dignity.

Some believe that sardonyx can boost confidence and strengthen natural assertiveness, particularly in leadership settings.

Care and Cleaning

Peridot: Gentle Handling for Lasting Beauty

Due to peridot’s perfect cleavage and relatively low hardness (6.5–7 on the Mohs scale), it is vulnerable to damage if not handled properly. Here are some care tips:

Avoid Heat and Sunlight Exposure: Prolonged exposure to sunlight can cause peridot to fade slightly, especially if it is of a lighter hue.
Cleaning: Use mild, warm soapy water and a soft cloth. Avoid ultrasonic cleaners, which may cause damage due to vibrations.
Storage: Store peridot separately from harder stones in a fabric-lined jewelry box or soft cloth pouch to avoid scratches.

Spinel: Durable and Resilient

Spinel is one of the most user-friendly gemstones in terms of care:

Hardness and Toughness: With a hardness of 8 and no cleavage, spinel is highly resistant to wear and tear.
Cleaning: Use warm soapy water and a soft cloth. Ultrasonic and steam cleaners are generally safe, but be cautious with pieces that include organic materials like pearls.
Storage: Spinel can be stored with other gems without the risk of scratching or damage. A soft cloth lining is ideal.

Sardonyx: Simple and Safe Maintenance

Sardonyx is a durable gem with a hardness of 6.5–7.5, making it relatively easy to care for:

Cleaning: Use a soft cloth with mild soap and water. Dry the stone carefully to avoid water spots.
Avoid Harsh Chemicals: Ammonia, bleach, and strong detergents should be avoided, as they can dull the stone’s luster.
Storage: Store sardonyx in a jewelry box away from abrasive surfaces. It can be kept with other similar hardness stones.

Conclusion

The August birthstone trio—peridot, spinel, and sardonyx—offers a unique and varied selection of gemstones, each with its own distinct history, properties, and symbolism. Peridot, the traditional choice, continues to hold its place in the hearts of gemstone lovers with its vibrant green hue. Spinel, named just over a decade ago, brings a new level of sophistication and excitement to the August birthstone lineup, while sardonyx, with its long-standing heritage in carved art, serves as a reminder of the beauty and craftsmanship that can be achieved with simpler, yet significant, stones.

For those born in August, these gemstones represent not only personal charm or fashion but also a rich cultural legacy and natural beauty. Whether you choose a lively peridot, a noble spinel, or a detailed sardonyx carving, each option provides a meaningful way to celebrate your birthstone and the month of August.