For those born in the eighth month of the year, the choice of a birthstone is not a single decision but a trio of distinct possibilities. August is unique among the months in having three official birthstones: peridot, spinel, and sardonyx. This diversity offers August-born individuals a remarkable spectrum of color, history, and symbolism to choose from. Each stone carries its own ancient legacy, geological origin, and metaphysical significance, reflecting the vibrant and varied energy of the summer month. From the luminous green of peridot, forged in the Earth’s mantle and found in meteorites, to the underappreciated brilliance of spinel, long mistaken for ruby, and the layered bands of sardonyx, a stone with a history spanning over 4,000 years, the August birthstones provide a rich tapestry of options. This article will explore the unique characteristics of each gem, delving into their geological formation, gemological properties, historical lore, and their journey to becoming modern birthstones, providing a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore: A Journey Through Time
The history of August’s birthstones is as layered as the sardonyx itself, weaving through ancient civilizations, royal courts, and modern gemological standards. The evolution from a single traditional stone to a trio of official gems reflects a growing desire for variety, accessibility, and personal expression in the world of jewelry.
The Traditional Foundation: Sardonyx
Sardonyx holds the distinction of being the original August birthstone, with a documented history that dates back more than 4,000 years. As a form of onyx, it is a banded chalcedony, a microcrystalline variety of quartz. Its name derives from the Greek words sard (a reddish-brown chalcedony) and onyx (meaning “veined” or “nail”). This stone was highly prized in the ancient world for its durability and distinctive appearance. Roman soldiers wore sardonyx rings and amulets carved with images of Mars, the god of war, believing the stone would grant them courage and protection in battle. Its use extended to signets and cameos, where the contrasting bands of color provided a perfect canvas for intricate relief carvings. For millennia, sardonyx was the sole birthstone associated with August, representing strength, stability, and protection.
The Official Addition: Peridot
The modern birthstone list for August was first formalized in 1912 by the National Association of Jewelers (now Jewelers of America), which designated peridot as the official August birthstone. This decision was influenced by peridot’s increasing availability and its distinctive, vibrant color. Peridot’s history, however, is far older and often intertwined with other famous green gems. The yellowish-green to greenish-yellow variety of the mineral olivine has been mistaken for emerald throughout history. The Shrine of the Three Holy Kings in Germany’s Cologne Cathedral is adorned with 200 carats of gems that were long believed to be emeralds but are now confirmed to be peridot. Some historians even speculate that Cleopatra’s famed emerald collection may have actually been composed of peridot. The gem’s name is believed to derive from the Arabic faridat, meaning “gem,” underscoring its ancient value. Its association with the Egyptian island of Zabargad (formerly Topazios), a source of peridot for over 3,500 years, further cements its place in gemological history.
The Modern Inclusion: Spinel
The most recent addition to the August birthstone family is spinel, officially recognized by the American Gem Trade Association (AGTA) and Jewelers of America in 2016. This inclusion was a long-overdue correction of a historical oversight. For centuries, red spinel was mistaken for ruby, a gem with which it shares a similar color range and crystalline structure. Some of the world’s most famous “rubies,” such as the Black Prince’s Ruby and the Timur Ruby in the British Crown Jewels, are, in fact, red spinels. This mistaken identity led to spinel being underappreciated as a distinct gemstone. Its recent elevation to birthstone status acknowledges its unique beauty, durability, and the growing consumer demand for alternatives to more traditional (and often more expensive) colored gems. Spinel’s journey from a supporting actor in gemological history to a celebrated lead role reflects a modern appreciation for its diverse color palette and intrinsic value.
Geological Formation and Sources
The three August birthstones originate from vastly different geological processes, resulting in unique formations and mining locations across the globe.
Peridot: From the Mantle to Meteorites
Peridot’s formation is particularly extraordinary. It is one of the few gemstones found in the Earth’s mantle, the layer between the core and the crust. Here, under immense heat and pressure, olivine crystallizes. This material is then brought to the surface by violent volcanic activity, often embedded within basaltic lava. The gemstone can also be found in alluvial deposits, eroded from these host rocks over millennia. Even more remarkably, peridot has been identified in meteorites that have fallen to Earth from outer space, such as the pallasite meteorites. This extraterrestrial origin adds a cosmic dimension to the gem’s allure. Key historical and modern sources include: * Egypt: The island of Zabargad (Topazios) in the Red Sea is the oldest recorded source, exploited since at least 1500 B.C. * Myanmar: Known for high-quality peridot. * Pakistan: The Kohistan-Eagle region produces significant quantities. * China: A major source of commercial-grade peridot. * United States: Deposits are found in Arizona (San Carlos Reservation), New Mexico, and Hawaii. * Other Locations: Tanzania, Vietnam, and Australia also contribute to the global supply.
Spinel: Formed in Metamorphic Environments
Spinel is a magnesium aluminum oxide (MgAl₂O₄) that typically forms in metamorphic rocks, particularly in magnesium-rich limestones and dolomites that have undergone high-temperature and high-pressure conditions. It can also form in alluvial placers, where it is weathered from its host rock and concentrated by water action. Unlike peridot, spinel is not associated with volcanic or extraterrestrial origins. Its primary sources are often linked to the same geological belts that produce rubies and sapphires. * Myanmar (Burma): The Mogok region is historically the most famous source, producing the finest red and pink spinels (often called “balas rubies”). * Tajikistan: The Kuh-i-Lal mine is a significant source of high-quality red and blue spinels. * Vietnam: Produces spinel in association with ruby deposits. * Sri Lanka: A source for a variety of spinel colors. * Other Locations: Afghanistan, Cambodia, and Brazil also have spinel deposits.
Sardonyx: A Layered Variety of Chalcedony
Sardonyx is not a distinct mineral but a banded variety of chalcedony, which itself is a microcrystalline form of quartz (SiO₂). It forms in low-temperature environments, typically in cavities or veins within volcanic or sedimentary rocks. Silica-rich solutions deposit layers of silica (quartz) in alternating bands of color. The red-brown bands are composed of sard (iron-oxide impurities), while the white or black bands are pure or carbon-included chalcedony. This banded formation is what gives sardonyx its characteristic appearance. Major sources include: * India: Historically a primary source, particularly for carved sardonyx. * Brazil: A significant modern producer. * United States: Deposits are found in Oregon and California. * Other Locations: Germany, Madagascar, and Uruguay also yield sardonyx.
Gemological Properties
Understanding the physical and chemical properties of these gems is essential for identification, valuation, and care. The following table summarizes key gemological data for peridot, spinel, and sardonyx.
| Property | Peridot | Spinel | Sardonyx |
|---|---|---|---|
| Mineral Family | Olivine (Forsterite-Fayalite series) | Spinel | Chalcedony (Quartz) |
| Chemical Formula | (Mg,Fe)₂SiO₄ | MgAl₂O₄ | SiO₂ (with iron oxide and carbon impurities) |
| Crystal System | Orthorhombic | Cubic | Trigonal (microcrystalline) |
| Hardness (Mohs) | 6.5 – 7 | 8 | 6.5 – 7 |
| Refractive Index | 1.635 – 1.690 | 1.712 – 1.762 | 1.535 – 1.539 |
| Specific Gravity | 3.28 – 3.48 | 3.58 – 3.61 | 2.58 – 2.64 |
| Luster | Vitreous (glassy) | Vitreous | Vitreous to waxy |
| Typical Colors | Yellowish-green to greenish-yellow | Red, pink, orange, purple, blue, black, colorless | Bands of red, brown, white, black |
| Transparency | Transparent to translucent | Transparent to opaque | Translucent to opaque |
| Key Distinguishing Features | Double refraction; often has inclusions (lily pads) | Single refraction; high refractive index; excellent clarity | Banded appearance; hardness; lower refractive index |
Peridot
Peridot’s defining characteristic is its consistent green color, ranging from yellowish-green to olive green, due to iron content. Its hardness of 6.5 to 7 on the Mohs scale makes it suitable for most jewelry, though it can be prone to scratching and requires careful handling. A key diagnostic feature is its double refraction, which can be observed under magnification. Peridot often contains small, disc-like inclusions that resemble lily pads, which are considered a hallmark of natural stones.
Spinel
Spinel is renowned for its exceptional hardness (8 on the Mohs scale), making it one of the most durable colored gemstones, highly resistant to scratching and wear. It is singly refractive, which helps distinguish it from similar-looking gems like ruby. Its high refractive index gives it a brilliant luster. Spinel’s most famous color is a vivid red, but it occurs in a rainbow of hues, including the rare blue and the prized “cobalt blue” spinel. The presence of iron can produce black or dark green varieties, while chromium and vanadium create reds and pinks.
Sardonyx
As a variety of chalcedony, sardonyx has a lower hardness (6.5 to 7) and a lower specific gravity than peridot or spinel. Its most prominent feature is the distinct banding of alternating layers of sard (reddish-brown) and onyx (white or black). This layered structure makes it ideal for cameo carving, where a raised figure is carved from the white layer against a dark background. Its translucency and waxy luster differentiate it from the glassy appearance of the other two August stones.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, all three August birthstones are imbued with rich symbolic meanings and metaphysical properties that have been cherished across cultures and eras.
Peridot: The Stone of the Sun and Prosperity
Peridot has long been associated with light, the sun, and vitality. In ancient Egypt, it was called the “gem of the sun,” believed to protect against nightmares and evil spirits. Its radiant green hue is linked to growth, renewal, and abundance. The name “peridot” is sometimes said to derive from the Greek word peridona, meaning “giving plenty,” which aligns with its reputation for attracting prosperity and good fortune. In modern crystal healing, peridot is considered a Heart Chakra stone, promoting emotional balance, releasing negative patterns, and opening the heart to love and joy. It is seen as a stone of positivity, confidence, and uplifting energy, making it a popular choice for those seeking to boost their mood and embrace a more optimistic outlook.
Spinel: The Stone of Renewal and Inspiration
Spinel’s symbolism is closely tied to its historical reputation as a stone of royalty and its modern role as a gem of revitalization. As the stone mistaken for rubies in royal crowns, it carries an aura of prestige and power. Metaphysically, spinel is regarded as a high-energy stone that restores energy and vitality. Different colors are associated with specific intentions: red spinel for passion and courage, blue for communication and calm, and black for grounding and protection. It is believed to inspire hope, encourage perseverance through hard times, and stimulate creativity. For those born in August, spinel is often chosen as a stone for personal renewal, helping to overcome stagnation and move forward with inspiration and strength.
Sardonyx: The Stone of Strength and Protection
With its ancient roots in warfare and signet rings, sardonyx is fundamentally a stone of strength, courage, and protection. Its banded layers symbolize stability and the building of strong foundations. Historically, it was used as a talisman for soldiers and leaders to ensure steadfastness in battle and clear decision-making. In metaphysical traditions, sardonyx is considered a deeply grounding stone that provides a sense of security and shields the wearer from negative energies. It is associated with fostering stable relationships, enhancing self-discipline, and promoting integrity. For those seeking a connection to history and a sense of unwavering support, sardonyx offers a powerful, earthy energy that supports courage and steadfastness.
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 storage guidelines.
Peridot Care
With a hardness of 6.5 to 7, peridot is moderately durable but can be scratched by harder materials. It is also somewhat susceptible to thermal shock and should not be exposed to sudden, extreme temperature changes. To clean peridot, use warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as the vibrations and heat can cause fractures in stones with inclusions. Store peridot jewelry separately in a soft cloth to prevent scratches from other gems.
Spinel Care
Spinel is one of the most durable colored gemstones, with a hardness of 8. It is resistant to scratching and can withstand more rigorous cleaning methods. Spinel can generally be cleaned safely with an ultrasonic cleaner and warm, soapy water. However, if the stone has been fracture-filled (a common treatment for lower-quality material), ultrasonic cleaning should be avoided. Steam cleaning is also typically safe for untreated spinel. Its durability makes it an excellent choice for everyday jewelry, such as rings and bracelets.
Sardonyx Care
As a variety of chalcedony with a hardness of 6.5 to 7, sardonyx requires gentle care similar to peridot. It should be cleaned with warm, soapy water and a soft brush. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaners, which could damage the stone or affect any dyes used to enhance color (though natural sardonyx is typically untreated). Due to its layered structure, sardonyx can be more prone to chipping if struck with force, so it should be stored carefully, ideally in a padded compartment or soft pouch, away from harder gems.
Conclusion
The three birthstones of August—peridot, spinel, and sardonyx—offer a remarkable diversity that reflects the multifaceted nature of the month itself. From the solar glow of peridot, a gem forged in the Earth’s mantle and the cosmos, to the vibrant versatility of spinel, a stone that has emerged from the shadow of ruby, and the ancient, layered strength of sardonyx, each stone provides a unique narrative of geological wonder, historical significance, and symbolic power. This trio allows individuals born in August to choose a gem that not only complements their aesthetic preferences but also resonates with their personal journey—whether seeking the joy and abundance of peridot, the renewal and inspiration of spinel, or the courage and protection of sardonyx. Together, they celebrate the warmth, strength, and enduring beauty of the summer month, offering timeless connections to the natural world and human history.