August is a unique month in the gemological calendar, distinguished by its association with not one, but three distinct and historically rich birthstones: peridot, spinel, and sardonyx. This trio offers a remarkable spectrum of color, origin, and meaning, providing those born in the eighth month with a diverse palette of choices. While peridot stands as the primary and most recognized gemstone for the month, celebrated for its signature lime-green hue, spinel and sardonyx are officially recognized alternatives, each with a fascinating backstory. Peridot, often called the "gem of the sun," is linked to light and renewal. Spinel, frequently mistaken for ruby throughout history, dazzles in a wide array of colors. Sardonyx, with its striking bands, offers an ancient charm and a connection to classical antiquity. Together, these gems represent the fullness of the summer season, offering unique benefits in beauty, symbolism, and energetic support for the August-born individual.
History and Lore
The history of August's birthstones is a journey through ancient civilizations, royal treasures, and enduring myths. Each stone carries a narrative that has evolved over millennia.
Peridot: The Gem of the Sun
Peridot holds a distinguished position among ancient gemstones. Its most significant historical source was Zabargad, an island in the Red Sea, which was the primary source for peridot for thousands of years. Egyptian pharaohs were among its most ardent admirers, valuing the gem for its protective qualities. They believed peridot could ward off the "terrors of the night" and evil spirits, often embedding it in jewelry and sacred objects. The stone was so cherished that it was referred to as the "Evening Emerald," a testament to its luminous glow that remained visible even under candlelight.
Beyond Egypt, peridot was also a gem of significance in ancient Rome. Roman scholars wore peridot amulets to promote foresight and protect against enchantment. The stone's association with light and the sun is a recurring theme across these ancient cultures, solidifying its reputation as a gem of positivity and renewal. Its origins deep within the Earth's mantle, brought to the surface by volcanic activity, further contributed to its mystical allure, linking it to the powerful forces of the planet itself.
Spinel: The Great Impostor and a Treasure in Its Own Right
Spinel's history is intertwined with that of the ruby, from which it is often indistinguishable to the untrained eye. For centuries, magnificent red spinels were mistaken for rubies and became part of royal regalia. The most famous of these is the "Black Prince's Ruby," a massive red spinel that has been part of the British Crown Jewels since the 14th century. Similarly, the "Timur Ruby," another colossal red spinel, has a storied past in the Mughal and Persian empires.
This history of mistaken identity, while overshadowing spinel's individual recognition for a time, also cemented its status as a gem of immense value and beauty. It was only in the late 18th century that mineralogists began to formally distinguish spinel from ruby based on its distinct crystal structure and chemical composition. Despite this, spinel's legacy as a treasured gem of kings and emperors remains, and it has emerged from ruby's shadow to be appreciated for its own brilliant sparkle and wide range of vibrant colors.
Sardonyx: The Stone of Courage and Eloquence
Sardonyx is perhaps the most ancient of the three, with a history deeply rooted in classical antiquity. As a variety of chalcedony (a microcrystalline quartz), it was highly prized by the Greeks and Romans. Its distinctive bands of reddish-brown sard and white onyx were carved into cameos and intaglios, creating exquisite works of art. Sardonyx was not merely decorative; it was a stone of great symbolic power.
It was believed to bestow courage, strength, and eloquence upon its wearer. Warriors would wear sardonyx amulets into battle for protection, while orators would use it to enhance their public speaking and persuasion. Its use in signet rings was practical, as wax did not stick to its smooth surface, but it also carried the authority and identity of its owner. This association with steadfastness and clear communication has made sardonyx a timeless symbol of integrity and personal power.
Geological Formation and Sources
Understanding the origin of these gems reveals the incredible natural processes that create them, from the Earth's deep mantle to its volcanic landscapes.
Peridot: A Gem from the Depths
Peridot has a unique origin story that sets it apart from most other gemstones. While many gems form in the Earth's crust, peridot is one of the few that originate deep within the Earth's mantle, at depths of 20 to 50 miles. It is brought to the surface through tectonic activity and volcanic eruptions. This deep-earth formation is shared only with diamonds, making peridot a particularly special gem. The chemical composition of peridot is relatively simple; it is the gem variety of the mineral olivine, with the formula (Mg, Fe)₂SiO₄. Its characteristic green color comes from the presence of iron.
Historically, the most famous source was Zabargad in the Red Sea. Today, however, significant sources of peridot include Pakistan, which produces some of the finest quality crystals, as well as Arizona in the United States, Myanmar, and Brazil.
Spinel: Formed in Metamorphic Environments
Spinel forms under high temperatures and pressures, typically in metamorphic rocks like marble and in alluvial deposits. Its chemical formula is MgAl₂O₄, and its color variations are due to trace elements such as chromium (for red and pink), iron (for blue and black), and vanadium. The most prized red spinel, often compared to ruby, comes from the famed "Mogok" region of Myanmar (Burma). Other important sources include Vietnam, which produces vibrant red and pink spinels, and Sri Lanka and Tanzania, known for a variety of colors including the rare and coveted "cobalt blue" spinel.
Sardonyx: A Variety of Chalcedony
Sardonyx is not a distinct mineral but a variety of banded chalcedony, which itself is a variety of quartz. It forms in low-temperature environments, typically as a secondary mineral in volcanic rock cavities or as nodules in sedimentary deposits. The distinct bands are created by alternating layers of sard (a reddish-brown variety of chalcedony) and onyx (a black and white variety). Major sources for high-quality sardonyx include India, which is known for its beautifully carved cameos, as well as Brazil, Germany, and the United States.
Gemological Properties
The physical and chemical characteristics of these three gems are as diverse as their colors and histories.
| 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) | 6.5 - 7 | 8 | 7 |
| Refractive Index | 1.65 - 1.69 | 1.718 | 1.53 - 1.54 |
| Luster | Vitreous (glassy) | Vitreous | Vitreous to waxy |
| Typical Colors | Olive to lime green | Red, pink, orange, violet, blue, black | Banded reddish-brown and white |
Peridot
Peridot registers a hardness of 6.5 to 7 on the Mohs scale, making it durable enough for most jewelry but susceptible to scratching by harder materials. Its refractive index ranges from 1.65 to 1.69. A key gemological feature of peridot is its "double refraction," where a single ray of light splits into two as it passes through the gem. This can sometimes be seen with the naked eye, causing the edges of the stone to appear doubled. Peridot is almost always a shade of green, varying from yellow-green to olive, with its color intensity determined by its iron content.
Spinel
Spinel is a significantly harder and more durable gemstone, rating an 8 on the Mohs scale. This makes it an excellent choice for all types of jewelry, including rings that are worn daily. Its refractive index is 1.718, and it has a high dispersion (the "fire" seen in diamonds), though it is often cut to emphasize its brilliance over fire. Spinel is singly refractive, unlike peridot. It is prized for its exceptional range of colors, from the classic "ruby red" to soft pinks, vibrant oranges, and the highly sought-after "cobalt blue."
Sardonyx
As a variety of quartz, sardonyx has a hardness of 7 on the Mohs scale, making it quite durable. Its refractive index is lower than that of peridot and spinel, typical for quartz (1.53-1.54). Its most defining characteristic is its banding. The appeal of sardonyx lies in the sharp contrast and pattern of its layers, which are often enhanced through cutting and carving. While it lacks the brilliance of peridot or spinel, its unique appearance and historical significance make it a valued gem for connoisseurs.
Symbolism and Metaphysical Beliefs
Throughout history, gemstones have been imbued with symbolic meanings and attributed with healing properties. The August birthstones are rich in such lore.
- Peridot: Known as the "gem of the sun," peridot is associated with light, positivity, and abundance. It is believed to promote growth, renewal, and prosperity. Its protective qualities, cherished by ancient Egyptians, are said to ward off negativity and nightmares. Metaphysically, peridot is linked to the heart chakra, fostering love and emotional healing.
- Spinel: This gem is a stone of renewal and revitalization. It is said to inspire a new sense of hope and energy, helping to overcome lethargy and exhaustion. Red spinel, in particular, is associated with passion and physical vitality. It is also believed to promote mental clarity and resolve conflicts.
- Sardonyx: As a stone of courage and strength, sardonyx has long been a talisman for warriors and leaders. It is also associated with eloquence and clear communication, making it a powerful stone for public speakers and those in positions of authority. On a deeper level, sardonyx is believed to promote integrity and virtuous conduct, grounding its wearer in a sense of stability and purpose.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone. The different hardness levels and characteristics of peridot, spinel, and sardonyx require specific attention.
Caring for Peridot
With a hardness of 6.5 to 7, peridot is relatively durable but can be scratched by harder gems like diamonds, sapphires, and rubies. It is best to store peridot jewelry separately in a soft cloth or lined box. To clean peridot, use warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaners, as the stone's inclusions can make it susceptible to damage from sudden temperature changes. Chemicals, especially harsh household cleaners, should be avoided as they can dull or damage the gem's surface.
Caring for Spinel
Spinel is one of the most durable of the birthstones, thanks to its 8 Mohs hardness rating. It is an excellent choice for rings and everyday wear. Cleaning spinel is straightforward; it can be safely cleaned with warm soapy water and a soft brush. It is also generally stable under ultrasonic and steam cleaners, though it is always wise to ensure the stone is secure in its setting before using such methods. As with all fine jewelry, it is advisable to have the setting checked regularly by a professional jeweler.
Caring for Sardonyx
Sardonyx, with a hardness of 7, is also quite durable. It can be cleaned using the same method as spinel: warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but caution is advised if the stone has been dyed or treated in any way. Because sardonyx is often carved into intricate cameos, special care should be taken to clean the crevices and details of the carving without using excessive pressure that could damage the delicate features.
Conclusion
The birthstones of August—peridot, spinel, and sardonyx—offer a compelling narrative of geological wonder, historical depth, and symbolic power. From the sun-kissed green of peridot, born from the Earth's fiery mantle, to the brilliant and often-misunderstood sparkle of spinel, and the ancient, banded strength of sardonyx, this trio provides a perfect gem for every personality and preference. Whether chosen for its vibrant color, its connection to ancient royalty, or its attributes of courage and renewal, an August birthstone is more than a piece of jewelry; it is a link to a rich and diverse gemological heritage.