The month of August is uniquely distinguished in the gemological calendar by possessing not one, but three official birthstones. This triad offers a remarkable spectrum of color, history, and symbolism, providing those born in this summer month with a diverse array of choices. The official birthstones for August are peridot, spinel, and sardonyx. Each gem possesses a distinct character, from the vibrant, single-hued green of peridot to the versatile array of colors found in spinel and the bold, layered bands of sardonyx. The existence of multiple stones is a relatively modern development, designed to offer consumers greater variety in color, affordability, and availability.
Peridot, with its signature lime-green glow, is the primary modern August birthstone. It is a gem-quality variety of the mineral olivine, celebrated for its distinctive color which is caused by its iron content, a feature that sets it apart from many other colored stones. Spinel, often mistaken for ruby throughout history, has recently gained recognition as a standalone gem of great beauty and resilience. It appears in a wide range of hues, from vivid red to soft pink, orange, blue, and even black. Sardonyx, the traditional and most ancient of the three, is a form of onyx characterized by its striking layers of red or brown sard and white onyx. This article will explore the history, geological origins, gemological properties, and symbolism of these three captivating August birthstones.
History and Lore
The history of the August birthstones is as varied as the gems themselves, spanning millennia and crossing numerous cultures. Sardonyx, the original August birthstone, boasts the longest documented history, with its use dating back more than 4,000 years. Its name is derived from the Greek words "sard" and "onyx," referring to its reddish-brown (sard) and banded (onyx) appearance. This gem was highly prized in ancient Rome, where it was frequently used for cameos and intaglios. Roman soldiers wore sardonyx rings, believing the stone would grant them courage and protection in battle. Its association with strength and stability made it a popular choice for seals and signet rings, as its layered structure allowed for intricate carving.
Peridot’s history is equally rich, though often shrouded in confusion with other green gemstones. The name "peridot" is believed to originate from the Arabic word "faridat," meaning gem. This August birthstone was valued in many ancient and medieval cultures. One of the most famous sources of ancient peridot was the island of Topazios in the Red Sea. Despite its name, which is a purported source for the gemstone topaz, the island actually produced peridot. This historical mix-up led to peridot often being mistaken for emerald. Many "emeralds" found in medieval European cathedral treasures have since been identified as peridot. The Shrine of the Three Holy Kings in Germany’s Cologne Cathedral, for example, is decorated with 200 carats of gems once believed to be emeralds, which are in fact peridot. Some historians even speculate that Cleopatra’s famous emerald collection may have been composed of peridot.
Spinel’s history is defined by its long-standing case of mistaken identity. For centuries, the most prized red spinels were misidentified as rubies. The "Black Prince's Ruby," a massive red gem set in the British Imperial State Crown, is a famous example of a red spinel that was mistaken for a ruby. The gem was acquired in the 14th century and was believed to be a ruby for over 400 years. This confusion persisted until modern gemology could definitively distinguish between the two. As a result, spinel was often underappreciated, viewed merely as a "simulant" of ruby rather than a gem of intrinsic value. Its formal recognition as an official August birthstone in 2016 by the American Gem Trade Association (AGTA) and Jewelers of America (JA) marks a significant shift, acknowledging its unique beauty and distinct identity.
The journey of these gems to their modern status was a gradual one. Sardonyx remained the primary birthstone for August for centuries. Peridot was added to the official list in 1912, reflecting its growing popularity and availability. Spinel was the most recent addition, included in 2016 to provide August-born individuals with a broader palette of colors and a gem with a rich, though often misunderstood, history. This evolution highlights a trend in the birthstone industry toward inclusivity and consumer choice.
Geological Formation and Sources
The origins of the August birthstones are as diverse as their appearance, with each gem forming under unique geological conditions.
Peridot: The Gem of the Mantle and Space
Peridot, the gem variety of the mineral olivine, is formed under extreme conditions. Unlike many gemstones that crystallize in the Earth's crust, peridot can be brought to the surface from deep within the Earth's mantle. This process often occurs through volcanic activity, where molten rock carries the crystals upward. It is not uncommon to find peridot embedded within hardened lava, a testament to its fiery origins. In a truly extraordinary twist, peridot is also found in meteorites that have fallen to Earth from outer space, making it one of the few gems known to have an extraterrestrial origin.
Historically, the most significant source of peridot was the island of Topazios (now Zabargad) in the Red Sea. This location was the primary source for ancient peridot gems. Today, peridot is mined in various locations around the world. Notable sources include Pakistan, which is known for producing high-quality peridot with a rich olive-green color, as well as Arizona in the United States, Myanmar, and Brazil.
Spinel: A Durable and Versatile Classic
Spinel is a magnesium aluminum oxide that forms in the metamorphic rocks of marble and alluvial deposits. It is often found in the same geological environments as ruby and sapphire, which is a key reason why it was so frequently confused with ruby. The gem's durability and range of colors make it a prized find for geologists and miners alike.
The primary sources for spinel are located in Southeast Asia. Myanmar (Burma) has historically been the source of the world's finest red spinels, often referred to as "balas ruby." Tajikistan is another key source, particularly for the vibrant pink and red spinels found in the Pamir Mountains. Vietnam and Sri Lanka also produce significant quantities of spinel in a variety of colors, including the highly sought-after vivid reds and brilliant blues.
Sardonyx: The Banded Beauty of the Earth
Sardonyx is a variety of the mineral chalcedony, which is a form of quartz. It is composed of alternating layers of sard (a reddish-brown variety of onyx) and onyx (a white or white-and-black variety). This banding is the result of different mineral impurities being deposited in layers as the quartz forms over long periods. The distinct layers are what give sardonyx its unique, banded appearance, which has made it so popular for carving and cameos.
Sardonyx is found in various parts of the world, including India, Brazil, Germany, and the United States. The quality of sardonyx is often judged by the sharpness and contrast of its bands. The most desirable stones have distinct, evenly spaced layers of rich red or brown sard and pure white onyx.
Gemological Properties
Understanding the physical and chemical properties of these gems is essential for gemologists, jewelers, and consumers. The following table summarizes the key gemological data for the three August birthstones.
| Property | Peridot | Spinel | Sardonyx |
|---|---|---|---|
| Mineral Family | Olivine | Spinel | Chalcedony (Quartz) |
| Chemical Formula | (Mg, Fe)2SiO4 | MgAl2O4 | SiO2 (with iron oxide impurities) |
| Crystal System | Orthorhombic | Cubic | Trigonal (Microcrystalline) |
| Hardness (Mohs Scale) | 6.5 - 7 | 8 | 7 |
| Refractive Index | 1.65 - 1.69 | 1.718 | 1.53 - 1.54 |
| Luster | Vitreous (Glassy) | Vitreous (Glassy) | Vitreous to Waxy |
| Typical Colors | Yellowish-green to olive green | Red, pink, orange, blue, black, purple | Red, brown, white, orange (banded) |
Color
The color of each August birthstone is one of its most defining characteristics. * Peridot: Its color is unique among gemstones. It occurs in only one color—green—though the shade can vary significantly. The presence of iron within its crystal structure determines the hue, ranging from bright yellow-green to a deeper olive or brownish-green. This vibrant, fresh green is often compared to the color of summer grass. * Spinel: This gem offers one of the widest color ranges of any gemstone. While the most prized color is a vivid, ruby-like red, spinel also occurs naturally in soft pinks, fiery oranges, rich purples, deep blues, and even a jet black. This variety makes it an exceptionally versatile gem for jewelry. * Sardonyx: The color of sardonyx is defined by its bands. The layers are typically shades of red, brown, and white. The contrast between the dark sard and the light onyx creates the stone’s signature pattern, giving it an earthy and natural aesthetic.
Hardness and Durability
Durability is a critical factor for any gemstone intended for jewelry. * Spinel is the most durable of the group, with a hardness of 8 on the Mohs scale. This makes it highly resistant to scratching and suitable for all types of jewelry, including rings and bracelets that see daily wear. * Peridot has a hardness of 6.5 to 7. While reasonably durable, it is softer than spinel and can be susceptible to scratching if not handled with care. It also possesses some "toughness" challenges, as it can be brittle due to its internal structure. * Sardonyx, with a hardness of 7, is also relatively durable. As a variety of quartz, it is resistant to scratching and can withstand normal wear, making it a good choice for cameos, intaglios, and cabochon-cut jewelry.
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been imbued with symbolic meaning and metaphysical powers. Each of the August birthstones carries its own distinct set of beliefs and associations.
- Peridot is strongly linked with light, positivity, and the sun. Ancient cultures believed it protected its wearer from evil spirits and nightmares. It is often called the "stone of the sun" due to its bright, cheerful color. In a modern context, peridot is associated with joy, abundance, and emotional clarity. It is believed to foster good fortune, peace, and success, and is often used to release negative patterns and open the heart to love and healing.
- Spinel is a stone of renewal and revitalization. Its vibrant energy is said to inspire hope, encourage new beginnings, and restore energy that has been lost through exhaustion or difficult times. It symbolizes inspiration, energy, and resilience. Some traditions also associate spinel with protecting the wearer from harm and promoting spiritual balance.
- Sardonyx, with its long history as a talisman of strength, is the quintessential stone of courage and protection. Roman soldiers valued it for its supposed ability to grant them stability and strength in battle. It is also associated with stable relationships and happy marriages, promoting mutual understanding and trust. Sardonyx stands for strength, stability, and protection, making it a powerful stone for those seeking grounding and security in their lives.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone. The different properties of peridot, spinel, and sardonyx dictate specific cleaning and handling instructions.
- Spinel: Due to its hardness of 8 and lack of cleavage, spinel is a very durable gem that is relatively easy to care for. It can be safely cleaned using warm, soapy water and a soft brush. It is resistant to most chemicals and can withstand ultrasonic and steam cleaning, although it is always wise to inspect the jewelry for any loose stones or settings first.
- Sardonyx: As a form of quartz, sardonyx is also quite durable. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but steam cleaning should be avoided if the stone has been fracture-filled or if it is set in a delicate antique mounting.
- Peridot: With a hardness of 6.5-7 and some brittleness, peridot requires more careful handling. It should be cleaned only with warm, soapy water and a soft brush. It is crucial to avoid ultrasonic cleaners and steam cleaners, as the vibrations and heat can cause fractures in the stone. Peridot should also be protected from harsh chemicals, such as those found in cosmetics and household cleaners, which can damage its surface luster. When storing peridot, it is best to keep it separate from other gems to prevent it from being scratched.
Conclusion
The birthstones of August—peridot, spinel, and sardonyx—offer a compelling narrative of geological wonder, historical depth, and symbolic richness. Together, they form a trio that provides an exceptional range of choices for anyone born in this month. Peridot captivates with its single, vibrant shade of green, a color born of both the Earth’s deep mantle and the vastness of space. Spinel, once a misunderstood gem, now shines in its own right, boasting a rainbow of colors and remarkable durability. Sardonyx, the ancient guardian, provides a connection to millennia of human history through its distinctive, earthy bands. From the fiery origins of peridot to the protective symbolism of sardonyx and the revitalizing energy of spinel, these gems are far more than mere adornments. They are enduring symbols of light, strength, and the unique identity of those born in the heart of summer.