August is a unique month in the calendar of birthstones, distinguished by its association with not one, not two, but three distinct gemstones: sardonyx, peridot, and spinel. This triad offers a remarkable spectrum of colors, histories, and geological origins, providing individuals born in this summer month with a diverse palette of choices. While sardonyx holds the title of the traditional birthstone, peridot is the modern official birthstone, and spinel was added in 2016 to expand the options. Each stone carries its own narrative, from ancient amulets to modern alternatives for more expensive gems. This article delves into the historical significance, geological formation, gemological properties, and symbolic meanings of August’s three birthstones, drawing exclusively from established sources to provide an expert overview for gemstone enthusiasts and collectors.
History and Lore: The Journey of August's Gems
The tradition of birthstones has deep roots in ancient cultures, with origins traceable to the biblical description of the Breastplate of Aaron, which featured twelve gemstones representing the twelve tribes of Israel. Over centuries, this concept evolved, and by the 18th century in Poland, Jewish gem traders began formally associating specific gemstones with each month of the year. The modern standardized list, however, was established much later. In 1912, the National Association of Jewelers (now known as Jewelers of America) officially updated the birthstone list, recognizing peridot as an additional birthstone for August alongside the traditional sardonyx. This addition reflected advancements in gemology and the broader availability of gem varieties. Decades later, in 2016, the Jewelers of America and the American Gem Trade Association further expanded the August lineup by adding spinel, aiming to provide more options for color, affordability, and appreciation of a gem often overshadowed by its lookalike, the ruby.
Sardonyx: The Traditional Birthstone Sardonyx is the original August birthstone, with a history that dates back more than 4,000 years. It is a variety of chalcedony, specifically composed of alternating layers of sard (a reddish-brown chalcedony) and onyx (a black chalcedony). This banded gem was treasured in ancient civilizations for its unique appearance and symbolism. The Romans and other ancient cultures prized sardonyx for its use in cameos and intaglios, where its contrasting bands could be carved to create intricate designs. It was believed to offer protection and was often worn as an amulet. Its deep historical roots make it the foundational stone of August’s birthstone trio.
Peridot: The Gem of the Sun Peridot, the vibrant green gemstone, has been admired for thousands of years. Its name derives from the Arabic word faridat, meaning "gem." Historically, peridot was frequently confused with other green stones, notably emerald and topaz. The Red Sea island of Topazios, which gave its name to topaz, actually produced peridot. In fact, some historians speculate that Cleopatra’s famous emerald collection may have been comprised of peridot. A notable historical example is the Shrine of the Three Holy Kings in Germany’s Cologne Cathedral, which is decorated with 200 carats of gems long believed to be emeralds but now identified as peridot. This gem was valued in many ancient and medieval cultures for its uplifting energy and was believed to protect against nightmares and bring happiness and strength to the wearer.
Spinel: The Underappreciated Alternative Spinel’s journey to becoming an official August birthstone is relatively recent, but its history is long and often misunderstood. For centuries, red spinel was mistaken for ruby, leading to its frequent misidentification in royal collections. The most famous example is the "Black Prince's Ruby" in the British Imperial State Crown, which is actually a red spinel. This historical confusion contributed to spinel being underappreciated until modern times. Its addition to the August birthstone list in 2016 was a deliberate effort to recognize its beauty and provide consumers with an alternative to ruby, a gem with which red spinel was mistaken for centuries.
Geological Formation and Sources
The three August birthstones originate from vastly different geological processes, which accounts for their distinct properties and appearances.
Sardonyx Formation and Sources Sardonyx is a cryptocrystalline form of silica, specifically a variety of chalcedony. It forms in volcanic and sedimentary environments where silica-rich solutions deposit layers in cavities or fissures, creating the characteristic banding. While specific mining locations for sardonyx are not detailed in the provided sources, its formation as a banded chalcedony typically occurs in regions with significant volcanic activity or sedimentary deposits containing silica.
Peridot Formation and Sources Peridot’s formation is particularly unique. It is the yellowish-green to greenish yellow gem variety of the mineral olivine. Peridot can be found in the hardened lava that carries it from deep within Earth’s mantle, as well as in meteorites that traveled from outer space. This dual origin—terrestrial and extraterrestrial—makes peridot one of the few gems formed under extreme conditions not only on Earth but also in space. While specific mining locations are not listed in the sources, its formation in mantle-derived lava and meteorites indicates a global distribution, with notable historical sources including the Red Sea island of Topazios.
Spinel Formation and Sources Spinel is a magnesium aluminum oxide with a cubic crystal structure. It forms in metamorphic rocks, particularly in magnesium-rich limestones and dolomites that have been subjected to high temperatures and pressures. Red spinel, the most sought-after variety, often forms in these same environments alongside ruby and sardonyx in certain geological settings. The sources do not specify exact mining locations for spinel, but its occurrence is typically associated with metamorphic terrains, such as those in Southeast Asia (e.g., Myanmar, Sri Lanka) and Africa, though these details are not explicitly mentioned in the provided chunks.
Gemological Properties
The physical and chemical characteristics of each gemstone define their durability, appearance, and care requirements. The following table summarizes key gemological properties based on the information provided in the sources.
| Gemstone | Chemical Composition | Hardness (Mohs Scale) | Color Range | Notable Properties |
|---|---|---|---|---|
| Sardonyx | Silica (SiO₂) - Chalcedony | 6.5 - 7 (Typical for chalcedony) | Layers of red-brown (sard) and black (onyx) | Banded, cryptocrystalline, often carved for cameos |
| Peridot | Olivine (Mg, Fe)₂SiO₄ | 6.5 - 7 | Yellowish green to greenish yellow, lime to olive | Forms in mantle lava and meteorites; often confused with emerald |
| Spinel | Magnesium Aluminum Oxide (MgAl₂O₄) | 8 | Vivid red, also pink, orange, blue, black | High hardness, often mistaken for ruby; cubic crystal structure |
Sardonyx As a variety of chalcedony, sardonyx has a hardness of approximately 6.5 to 7 on the Mohs scale, making it durable enough for everyday jewelry. Its cryptocrystalline structure gives it a waxy luster. The banding is its defining feature, and it is often cut en cabochon or carved for intaglios and cameos to highlight the contrast between layers.
Peridot Peridot, with a hardness of 6.5 to 7, is moderately durable but can be prone to scratching if not handled carefully. Its chemical composition as olivine gives it a distinctive green hue that does not fade with heat or light exposure. The gem’s formation in extreme environments—both terrestrial and extraterrestrial—adds to its uniqueness. Its refractive index and specific gravity are typical for olivine, though these exact figures are not provided in the sources.
Spinel Spinel is one of the harder gemstones, with a Mohs hardness of 8, making it highly suitable for all types of jewelry, including rings. Its durability is comparable to that of ruby and sapphire. Spinel’s crystal system is cubic, which contributes to its excellent brilliance and fire when cut properly. The most prized color is a vivid red, but it occurs in a wide spectrum, including pink, orange, blue, and black.
Symbolism and Metaphysical Beliefs
Across cultures, these gemstones have been attributed with various symbolic meanings and metaphysical properties, often linked to their colors and historical uses.
Sardonyx Historically, sardonyx was associated with protection and courage. Ancient warriors and Romans wore it as an amulet for safety in battle. Its banded structure was seen as a symbol of harmony between different elements, and it was often used in seals and signets, representing authority and integrity.
Peridot Peridot has been called the "gem of the sun" due to its bright, uplifting green color. It was believed to bring happiness, strength, and protection against nightmares. In ancient cultures, it was thought to ward off evil spirits and promote confidence and valor—traits associated with the zodiac sign Leo, which governs the month of August. Its connection to the sun also made it a symbol of growth and renewal.
Spinel Spinel’s symbolism is largely tied to its historical misidentification with ruby. As a result, it inherited some of ruby’s traditional associations with vitality, passion, and energy. In modern metaphysical beliefs, spinel is often regarded as a stone of rejuvenation and renewal, helping to revitalize the wearer’s energy and passion for life. Its variety of colors allows for different symbolic interpretations, with red spinel representing energy, blue spinel for calm, and pink for love.
Care and Cleaning
Proper maintenance is essential to preserve the beauty and longevity of these gemstones, based on their physical properties.
Sardonyx With a hardness of 6.5 to 7, sardonyx is relatively durable but can be scratched by harder materials. It is safe to clean with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes, as these could potentially damage the stone or affect the adhesive used in carved pieces.
Peridot Peridot, with a hardness of 6.5 to 7, requires careful handling to prevent scratches. It is best cleaned with warm, soapy water and a soft cloth. Avoid harsh chemicals, acids, and ultrasonic cleaners, as peridot can be sensitive to thermal shock and chemical exposure. Store it separately from harder gems to prevent abrasion.
Spinel Spinel’s high hardness of 8 makes it one of the most durable gemstones. It can be cleaned with warm, soapy water and a soft brush. It is generally safe for ultrasonic cleaning, but it is always advisable to check with a professional jeweler if the stone is set in a delicate or antique piece. Spinel’s durability makes it an excellent choice for rings and everyday wear.
Conclusion
August’s birthstones—sardonyx, peridot, and spinel—offer a remarkable diversity that reflects the month’s vibrant summer energy. Sardonyx, with its ancient heritage and banded beauty, serves as the traditional foundation. Peridot, the gem of the sun, provides a unique green hue with extraterrestrial origins and a history of being mistaken for emerald. Spinel, the recent addition, corrects centuries of misidentification by standing on its own merits as a durable and colorful alternative to ruby. Together, they embody a rich tapestry of geological wonders, historical narratives, and symbolic meanings. For those born in August, this triad presents a unique opportunity to choose a gemstone that resonates personally, whether drawn to history, color, or durability. As with all gemstones, proper care ensures that these treasures will endure as symbols of identity and beauty for generations to come.