Peridot, the gemstone designated for those born on August 12th, is a captivating variety of the mineral olivine, celebrated for its distinctive lime-green to yellowish-green hue. As the modern birthstone for August in the United States and the United Kingdom, it has supplanted sardonyx, the month's original representative. Its significance, however, stretches far beyond its contemporary designation. Peridot has been cherished for millennia, from the ancient Egyptian civilization that revered it as "the gem of the sun" to the medieval European churches that mistakenly adorned their treasures with it, believing it to be emerald. This article delves into the rich history, unique geological origins, precise gemological properties, and enduring cultural symbolism of peridot, providing a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
Peridot’s historical narrative is as vivid as its color. Its name is believed to be derived from the Arabic word faridat, meaning "gem," a testament to its long-standing appeal across diverse cultures. Throughout history, this green gemstone has frequently been confused with other prized jewels, a confusion that underscores both its value and its unique character. The Red Sea island of Topazios, a source of the name "topaz," was actually a renowned source of peridot, leading to centuries of misidentification between the two gemstones.
One of the most notable historical examples of this confusion is found in Germany’s Cologne Cathedral. The Shrine of the Three Holy Kings, dating back to the 12th century, is decorated with 200 carats of gems that were long believed to be emeralds. Modern examination revealed these gems to be peridots, a discovery that highlights the gemstone's historical significance and the prevalence of gem misidentification in earlier eras. This revelation has led some historians to speculate that Cleopatra’s famous emerald collection may have, in part, been comprised of peridots, further elevating the gem's esteemed status in antiquity.
Peridot’s use as a birthstone is a relatively modern development. The original birthstone for August was sardonyx, a banded variety of chalcedony. In the early 20th century, peridot was adopted as the primary August birthstone in the United States and the United Kingdom. This transition was likely influenced by the gemstone’s striking beauty, increasing availability, and growing popularity in jewelry design. While sardonyx remains a traditional alternative, peridot now stands as the definitive modern birthstone for the month, a position it has held for over a century.
Geological Formation and Sources
Peridot is the yellowish-green to greenish yellow gem variety of the mineral olivine, with the chemical formula (Mg, Fe)₂SiO₄. Its formation is one of the most fascinating aspects of its geology, as it is created under extreme conditions. Peridot can be found in the hardened lava that carries it from deep within Earth’s mantle, and it is also one of the few gems that have been identified in meteorites that traveled from outer space. This dual origin—terrestrial and extraterrestrial—makes peridot a truly unique gemstone in the mineral kingdom.
The primary sources of peridot include the United States (notably Arizona), Australia, Brazil, China, Egypt, Kenya, Mexico, Myanmar (Burma), Norway, Pakistan, South Africa, Sri Lanka, and Tanzania. The gemstone’s color, which is its most defining characteristic, is determined by its iron content. The finest peridots display a vibrant, pure green color, often with a slight yellow tint, especially in smaller sizes. Larger stones, typically over 10 carats, tend to exhibit the most intense and favored green hues. While peridot itself is not considered rare, large stones of pure, vibrant green are scarce and command higher prices in the gem market.
Gemological Properties
Peridot possesses a distinct set of physical and optical properties that define its identity and inform its care and use in jewelry. As a member of the olivine group, it is a relatively hard gemstone, making it suitable for various types of jewelry, though it requires mindful handling.
The following table summarizes the key gemological properties of peridot, as derived from authoritative sources:
| Property | Description |
|---|---|
| Mineral | Olivine |
| Chemical Formula | (Mg, Fe)₂SiO₄ |
| Crystal System | Orthorhombic |
| Hardness (Mohs Scale) | 6.5 to 7 |
| Refractive Index | 1.654 - 1.690 (High double refraction) |
| Specific Gravity | 3.34 - 3.51 |
| Luster | Vitreous (glassy) |
| Transparency | Transparent to translucent |
| Color Range | Yellowish-green to greenish-yellow; pure green is most valued. |
| Typical Inclusions | Needles, crystals, and liquid inclusions; some stones may have "lily pad" inclusions. |
Peridot is known for its high double refraction, a property that can be observed with a loupe by looking through the gem at a single facet, where the edges may appear doubled. It has a vitreous luster and is typically transparent. The gem's hardness of 6.5 to 7 on the Mohs scale means it is moderately durable but can be scratched by harder materials. It is also important to note that peridot has no cleavage, which is a favorable characteristic for durability, but it is brittle and can be susceptible to chipping if struck with force.
Symbolism and Metaphysical Beliefs
Across cultures and centuries, peridot has been imbued with a rich tapestry of symbolic meanings and metaphysical beliefs. In ancient Egypt, peridot was known as "the gem of the sun" and was associated with nature deities, believed to offer protection and promote healing. It was thought to have the power to ward off evil spirits and bring good fortune to its wearer.
Hawaiian legend offers another poetic interpretation, describing peridot stones as the tears of the goddess Pele, the volcano goddess. This connection to volcanic origins aligns with the gem’s geological formation in lava flows. In modern metaphysical practices, peridot is often associated with strength, prosperity, and peace. For those born in August, it is believed to bring good luck, success, and calmness to their lives. Specific dates within the month, such as August 12th, are sometimes linked to unique energies; for example, August 12th is associated with the Perseid meteor shower, adding a celestial layer to its lore. These beliefs, while not scientifically proven, contribute to the gemstone's enduring appeal and cultural resonance.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of peridot jewelry. Given its hardness of 6.5 to 7 on the Mohs scale, peridot is moderately durable but should be protected from scratches and blows. It is harder than glass but softer than quartz, so it can be scratched by everyday materials like sand (which contains quartz). To prevent damage, it is advisable to store peridot jewelry separately from other gems and metals.
Cleaning peridot is straightforward. Use warm, soapy water and a soft brush to gently remove dirt and oil. Avoid ultrasonic cleaners and steam cleaning, as the gemstone's inclusions and potential for fracture can make it vulnerable to damage under intense vibrations or heat. After cleaning, rinse thoroughly and dry with a soft, lint-free cloth. With proper care, peridot jewelry can retain its vibrant green glow for generations.
Conclusion
Peridot stands as a gemstone of remarkable duality: a product of Earth's fiery interior and the cold vastness of space, a stone mistaken for emerald yet cherished in its own right, and a modern birthstone with ancient roots. Its vibrant green color, unique geological origins, and rich historical tapestry make it a subject of enduring fascination. For those born on August 12th, peridot is more than a birthstone; it is a symbol of strength, peace, and good fortune, connecting the wearer to a legacy that spans millennia. Whether set in a ring, pendant, or bracelet, peridot continues to captivate with its radiant glow, offering a touch of green brilliance to the world of gemstones.