Peridot, the vibrant green gemstone designated as the modern birthstone for August, has captivated humanity for millennia. Its distinct olive to lime-green hue, often likened to the fresh growth of spring or the sun's brilliant rays, sets it apart in the gemological world. Unlike many gemstones that owe their color to trace impurities, peridot’s green is an intrinsic property of its mineral composition. As a birthstone, it carries a legacy of historical reverence, geological intrigue, and enduring symbolism. This article delves into the multifaceted nature of peridot, exploring its journey from ancient Egyptian mines to modern jewelry boxes, its unique formation deep within the Earth, its defining gemological properties, and the cultural beliefs that have surrounded it throughout history. We will also provide practical guidance on its care, ensuring this captivating stone remains a brilliant testament to August's summer spirit.
History and Lore
The history of peridot is as rich and storied as its color. One of its most significant historical chapters unfolds in ancient Egypt, where the gemstone was known as "the gem of the sun." The Egyptians mined peridot on the Red Sea island of Topazios (now Zabargad), a perilous and treacherous endeavor that was often conducted under the cover of darkness. They believed the gemstone possessed the power to ward off evil spirits and nightmares, and its radiant green was associated with the sun god Ra. Historical accounts, including those from Pliny the Elder, suggest that the Egyptians prized peridot highly, using it in jewelry and religious artifacts. Its luminous quality was so pronounced that it was often mistaken for emeralds, even by royalty; some historians believe that many of the "emeralds" worn by Cleopatra were, in fact, peridots.
The gemstone's journey through history continued across continents. In the Middle Ages, peridot traveled along the Silk Road, where it was incorporated into the adornments of clergy and nobility. Its presence in European churches and cathedrals, set in gold, is a testament to its valued status. The peridot found in these medieval settings often originated from the same Egyptian source, though later discoveries would expand its geographic footprint.
The association of peridot with August as a birthstone is a relatively modern convention. The concept of assigning specific gemstones to each month evolved over time, with significant standardization occurring in the early 20th century. The first official modern birthstone list was released in the United States by the National Association of Jewelers in 1912. This list designated peridot as the primary birthstone for August, replacing the traditional stone, sardonyx. While sardonyx (a banded variety of onyx) was the historical birthstone for August, peridot’s vibrant color and growing availability made it a more appealing and popular choice for the modern era. This shift reflects a broader trend where birthstone lists have evolved, influenced by market trends, gemstone discoveries, and consumer preference. Today, peridot stands as the unequivocal modern birthstone for August, a symbol of summer's peak and a gem with a lineage stretching back to antiquity.
Geological Formation and Sources
Peridot’s formation is a fascinating geological process that distinguishes it from many other gemstones. It is one of the few gems that crystallizes deep within the Earth's mantle, far from the crust where most gemstones form. Peridot is the gem variety of the mineral olivine, with the chemical formula (Mg, Fe)₂SiO₄. Its formation requires specific conditions: high temperatures and pressures, and a silica-rich environment. It is brought to the surface through volcanic activity, often found in igneous rocks like basalt and in peridotite xenoliths (fragments of mantle rock) carried upward by magma. This unique origin means that peridot is one of the few gemstones that can be found in meteorites, specifically pallasite meteorites, where it formed in the vacuum of space.
While peridot is mined in various locations around the world, a few sources have been historically and commercially significant. The ancient Egyptian mines on Zabargad Island in the Red Sea were the primary source for centuries, supplying the gemstones that adorned pharaohs and priests. Although production from this location is limited today, its historical importance is undeniable.
In more recent times, the United States has become a notable source of peridot. The San Carlos Apache Reservation in Arizona is one of the world's most productive sources of gem-quality peridot. The gemstone is mined from volcanic rock in this region, and the Arizona peridot is known for its consistent quality and vibrant green color. Other U.S. sources include Hawaii, where peridot can be found in volcanic cinders.
Internationally, significant deposits are found in Myanmar (Burma), particularly in the Mogok region, known for its gemstone wealth. China also produces peridot, with mines in the Xinjiang region contributing to the global supply. Other sources include Australia, Brazil, South Africa, and Norway. The geographic diversity of peridot sources means that the gemstone's color and clarity can vary slightly depending on its origin, with some deposits yielding stones with a more yellowish-green hue and others producing a purer, intense green.
Gemological Properties
Peridot possesses a distinct set of physical and optical properties that define its character and inform its use in jewelry. Understanding these properties is crucial for gemologists, jewelers, and consumers alike.
Color: Peridot’s color is its most defining attribute, ranging from a light, yellowish-green to a deep olive-green. The most prized color is a rich, vibrant olive-green, often described as "lime" or "apple" green. The color is due to the presence of iron within its crystal structure; the specific shade is determined by the amount of iron. Unlike many colored gemstones, peridot’s color is consistent under different light sources, a property known as being "pleochroic" in a very subtle way. It typically shows no strong color change from natural to artificial light, making its color appear reliably green.
Hardness and Durability: On the Mohs scale of mineral hardness, peridot rates between 6.5 and 7. This makes it a relatively durable gemstone, suitable for various types of jewelry, including rings, earrings, and pendants. However, its hardness is lower than that of sapphire or ruby (Mohs 9) and diamond (Mohs 10). This means peridot can be scratched by harder materials and may show wear over time if used in rings that are subject to daily knocks. It also possesses distinct cleavage in two directions, which means it can break along certain planes if struck with sufficient force. This property requires careful cutting and setting to avoid damage.
Clarity and Inclusions: Peridot is typically found with some inclusions. Common inclusions can include small, dark mineral crystals (often spinel or magnetite), gas bubbles, and fluid inclusions. These inclusions are often accepted as part of the stone's character and do not typically detract from its beauty if they are not overly prominent. High-quality peridot is transparent with minimal visible inclusions, but even stones with inclusions can be very attractive. The presence of inclusions is a natural part of its formation and can help gemologists distinguish natural peridot from synthetic or imitated materials.
Refractive Index and Luster: Peridot has a refractive index range of approximately 1.64 to 1.69. This gives it a good brilliance when cut properly. It exhibits a vitreous (glass-like) luster, which contributes to its attractive shine. The combination of its color and luster makes peridot a visually appealing gemstone, especially when faceted to maximize light return.
Cut and Carat: Peridot is commonly cut into a variety of shapes, including rounds, ovals, emeralds, and cushions. Its good clarity and color allow for versatile cutting styles. Large peridot crystals are more common than with many other gemstones, so peridots over 10 carats are not exceptionally rare, though larger sizes still command premium prices. The gemstone's relative availability in larger sizes makes it an excellent choice for statement pieces.
The following table summarizes the key gemological properties of peridot:
| Property | Description |
|---|---|
| Mineral | Olivine (Mg, Fe)₂SiO₄ |
| Color | Olive green to yellowish-green; most prized is a rich, vibrant green. |
| Hardness (Mohs) | 6.5 - 7 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.64 - 1.69 |
| Specific Gravity | 3.27 - 4.37 (varies with iron content) |
| Luster | Vitreous (glass-like) |
| Transparency | Transparent to translucent |
| Common Inclusions | Mineral crystals, gas bubbles, fluid inclusions. |
| Special Properties | Pleochroism is weak; shows no strong color change under different light. |
Symbolism and Metaphysical Beliefs
Peridot has been attributed with a wide array of symbolic meanings and metaphysical powers across different cultures and eras. Its bright green color, reminiscent of nature and growth, naturally lends itself to associations with vitality, renewal, and prosperity.
In ancient Egypt, peridot was believed to be a "stone of the sun" and was thought to possess protective qualities against evil spirits and nightmares. It was also associated with healing and was believed to have the power to calm anger and soothe anxieties. The Egyptians wore peridot amulets and placed them in temples to honor their gods.
During the Middle Ages, peridot was considered a stone of friendship and peace. It was believed to bring happiness and good fortune to its wearer and was often given as a token of affection. Some traditions held that peridot could ward off depression and bring a sense of joy and optimism.
In modern metaphysical beliefs, peridot is often called the "evening emerald" due to its ability to glow in candlelight. It is associated with the heart chakra and is believed to promote emotional healing, compassion, and forgiveness. Many crystal healers use peridot to attract abundance and prosperity, both in material and spiritual forms. It is also thought to enhance confidence and assertiveness, helping the wearer to overcome past traumas and move forward with a positive outlook.
It is important to note that these symbolic and metaphysical beliefs are part of cultural and historical traditions. They are not scientifically verified and fall outside the realm of gemological properties. However, they contribute significantly to the gemstone's allure and its enduring popularity as a birthstone and a meaningful piece of jewelry.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of peridot jewelry. Due to its moderate hardness and cleavage, peridot requires some attention to avoid damage.
Cleaning: Peridot can be safely cleaned using warm, soapy water and a soft brush. Mild dish soap is effective for removing oils and dirt. It is crucial to rinse the stone thoroughly to remove any soap residue, which can leave a film. Ultrasonic cleaners are generally safe for peridot, but caution is advised if the stone has significant inclusions or fractures, as vibrations could potentially exacerbate existing weaknesses. Steam cleaning is not recommended, as the high heat and pressure could cause damage. Always avoid harsh chemicals, including bleach and strong acids, which can etch the surface of the gemstone.
Storage: When not being worn, peridot jewelry should be stored separately from other jewelry pieces to prevent scratching. A soft cloth pouch or a lined jewelry box with individual compartments is ideal. Avoid storing peridot with harder gemstones like diamonds, sapphires, or rubies, which could scratch its surface.
Wearing Considerations: While peridot is durable enough for everyday wear, it is best suited for jewelry that is less prone to impact, such as earrings, pendants, and bracelets. Rings, especially those intended for daily wear, should be chosen with care. A protective setting, like a bezel or a halo, can help shield the stone from knocks and scratches. It is advisable to remove peridot rings during activities that could subject them to hard blows, such as gardening, heavy lifting, or sports.
By following these care guidelines, owners of peridot jewelry can ensure that their gemstone retains its vibrant green color and brilliant luster for generations, serving as a beautiful and enduring symbol of August.
Conclusion
Peridot stands as a gemstone of remarkable distinction, bridging the ancient world and the modern era. From its origins in the Earth's mantle to its historical significance in Egyptian culture, it has consistently been valued for its unique, radiant green hue. As the official modern birthstone for August, it captures the essence of summer—vibrant, lively, and full of warmth. Its gemological properties, including its characteristic color, moderate hardness, and relative clarity, make it a versatile and attractive choice for a wide range of jewelry designs. While its symbolic meanings and metaphysical beliefs add layers of cultural depth, its primary appeal lies in its natural beauty and fascinating geological story. For those born in August, peridot offers a personal connection to a gemstone that is both historically profound and aesthetically captivating, a lasting treasure that embodies the spirit of its birth month.