Peridot, with its distinctive olive to lime-green hue, stands as a cherished gemstone and one of the three traditional birthstones for August. This beautiful yellow-green jewel is celebrated for its remarkable geological origin, accessible affordability, and historical lore. As a member of the olivine mineral family, peridot forms deep within the Earth's mantle and is brought to the surface by volcanic activity, a process that makes its formation uniquely tied to the planet's fiery heart. Unlike many gemstones, peridot occurs in only one color, though its shades range from yellowish-green to a rich, deep olive. Its durability, while not exceptional, makes it suitable for a variety of jewelry settings with proper care. This article delves into the history, geological formation, gemological properties, and cultural significance of peridot, drawing exclusively from authoritative sources to provide a comprehensive guide for enthusiasts, collectors, and students of gemology.
History and Lore
The history of peridot is ancient and steeped in legend, though its identification in historical records can be complex due to its similarity to other green gems. For centuries, peridot has been mistaken for emerald, topaz, and even sapphire. One of the most famous historical sources of peridot was the island of Zabargad (also known as St. John's Island) in the Red Sea, which supplied the Egyptian civilization. Historical accounts suggest that the ancient Egyptians mined peridot as early as the 15th century B.C., valuing it for its protective qualities and believing it could ward off nightmares and evil spirits. Cleopatra's famed emerald collection is now believed by some gemologists to have included significant amounts of peridot, highlighting the historical confusion between these two green gems.
The journey of peridot to becoming a modern birthstone is part of a broader evolution of birthstone lists. The concept of birthstones is often traced back to the Breastplate of Aaron described in the Old Testament, which featured twelve stones representing the tribes of Israel. Early Christian scholars like St. Jerome in the fifth century connected these twelve stones to the twelve months and zodiac signs. However, the custom of wearing stones corresponding to one's birth month appears to have originated much later, possibly in Poland during the eighteenth century.
The modern standardization of birthstone lists began in 1912 with the American National Retail Jewelers Association (now known as Jewelers of America). This list was created to reduce confusion and provide a clear guide for the industry. Peridot was included as the traditional birthstone for August. Over time, the list has seen modifications. For instance, tourmaline was added as an August birthstone to provide color choices beyond peridot's yellowish-green hue, and spinel was also added for its durability and color variety. These additions were made to offer consumers more options in terms of color, durability, and style. Today, peridot remains a primary and beloved birthstone for August, valued for its unique color and historical charm.
Geological Formation and Sources
Peridot's formation is a fascinating geological process that sets it apart from many other gemstones. It is a member of the olivine family, a group of minerals with the chemical formula (Mg,Fe)₂SiO₄. The gem-quality peridot we admire today is specifically forsterite-rich olivine. This mineral forms deep within the Earth's mantle, under conditions of extreme heat and pressure. It is brought to the surface through volcanic activity. When magma rises and erupts, it carries peridot crystals from the mantle to the crust. These crystals can be found in the volcanic rock itself, such as basalt, or can be weathered out and transported by water, eventually settling in riverbeds or coastal sands.
One of the most notable natural occurrences of peridot is in the sands of Hawaii. As peridot crystals from volcanic eruptions line the beaches, they are eventually collected and cut into gemstones. This direct link to volcanic activity gives peridot a unique origin story among gemstones.
Peridot is mined in several locations around the world, each producing stones with slightly different characteristics. The most historically significant source is the Red Sea's Zabargad island, which provided the gems for ancient Egyptian jewelry. Modern sources include: * Pakistan: Known for producing large, high-quality crystals of deep green peridot. * China: A significant source of peridot, often yielding stones with a lighter, more yellowish-green hue. * United States: Peridot is found in Arizona, particularly in the San Carlos Apache Reservation, which is one of the largest sources of gem-quality peridot in the world. * Other locations: Myanmar, Brazil, Australia, and Norway also have deposits of peridot.
The color of peridot from different sources can vary. Stones from Pakistan and Myanmar are often prized for their rich, deep olive-green color, while those from the United States and China may lean more towards a yellowish-green. The size of peridot crystals can also be substantial, with some specimens found weighing several hundred carats, making them suitable for large statement pieces of jewelry.
Gemological Properties
Understanding the gemological properties of peridot is essential for appreciating its value, durability, and care. As a member of the olivine family, peridot has a distinct set of physical and chemical characteristics that define it.
Chemical Composition and Crystal System: Peridot's chemical formula is (Mg,Fe)₂SiO₄. It is an iron magnesium silicate. The color of peridot is primarily determined by its iron content; higher iron concentrations result in a deeper green hue. Peridot crystallizes in the orthorhombic crystal system.
Color: Peridot is prized for its vibrant green color, which is caused by the presence of iron. It is one of the few gemstones that occurs in only one color, though the shade can range from yellowish-green to a deep olive. The most valued color is a rich, pure green without strong yellow or brown overtones.
Hardness and Durability: On the Mohs scale of hardness, peridot ranks between 6.5 and 7. This makes it moderately hard, but not as durable as gemstones like diamond, ruby, or sapphire. According to gemological durability ratings, peridot is classified as "fair to poor" due to its propensity for breakage. It is prone to chipping and abrasion, especially if subjected to sharp impacts. While it can be used in rings and bracelets, protective settings are recommended, and wearers should exercise caution to avoid hard blows.
Clarity and Inclusions: Peridot is typically free of visible inclusions, but it can contain small, needle-like inclusions known as "lily pads" (lilac-colored disc-shaped inclusions) or tiny black specks. These inclusions are generally accepted and do not significantly detract from the stone's beauty. Some peridot may also have gas-filled cavities.
Cut and Carat Weight: Peridot is cut into a variety of shapes to maximize its color and brilliance. Common cuts include oval, round, pear, and emerald cuts. Because peridot is available in larger sizes, it is often used as a centerpiece in jewelry. Large, clean peridots over 10 carats are rare and command premium prices.
Refractive Index and Specific Gravity: Peridot has a refractive index ranging from 1.65 to 1.69 and a specific gravity of 3.3 to 3.5. These properties help gemologists distinguish it from other green gemstones.
The following table summarizes the key gemological properties of peridot:
| Property | Value |
|---|---|
| Chemical Formula | (Mg,Fe)₂SiO₄ |
| Mineral Family | Olivine |
| Hardness (Mohs) | 6.5 - 7 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.65 - 1.69 |
| Specific Gravity | 3.3 - 3.5 |
| Durability Rating | Fair to Poor (prone to breakage) |
| Color | Yellowish-green to deep olive green |
Symbolism and Metaphysical Beliefs
Peridot has been attributed with various symbolic meanings and metaphysical powers throughout history. Ancient Egyptians believed that peridot could ward off evil spirits and protect against nightmares. It was often used in talismans and amulets for its protective qualities. The gemstone was also associated with the sun, and it was thought to possess the power to heal and bring prosperity.
In modern crystal healing and metaphysical practices, peridot is often called the "stone of compassion." It is believed to promote emotional healing, reduce stress, and attract abundance and good fortune. Some practitioners associate peridot with the heart chakra, suggesting it can help open the heart to love and forgiveness. While these beliefs are popular in certain communities, it is important to note that they are not supported by scientific evidence and fall outside the realm of formal gemology.
Peridot's association with August as a birthstone ties it to the astrological sign of Leo. Leos are often characterized as confident, generous, and creative, and peridot is said to enhance these traits, bringing warmth and vitality to the wearer.
Care and Cleaning
Due to its moderate hardness and propensity for breakage, peridot requires careful handling and maintenance to preserve its beauty. While it is suitable for everyday wear in earrings, pendants, and brooches, it is more vulnerable in rings and bracelets that are exposed to potential impacts.
Cleaning: Peridot can be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaners, as the vibrations and heat can cause fractures or exacerbate existing inclusions. After cleaning, rinse the stone thoroughly with clean water and dry it with a soft, lint-free cloth.
Storage: When not being worn, peridot jewelry should be stored separately from other gemstones to prevent scratching. It is best kept in a soft pouch or a lined jewelry box.
Precautions: Avoid exposing peridot to harsh chemicals, such as chlorine in swimming pools or household cleaners, as they can damage the stone's surface. It is also advisable to remove peridot jewelry before engaging in physical activities or manual labor to avoid impacts that could chip or crack the stone.
Conclusion
Peridot is a gemstone of remarkable beauty and unique geological origin. As the traditional birthstone for August, it offers a vibrant green hue that is both affordable and accessible. Its formation deep within the Earth's mantle and its journey to the surface via volcanic activity give it a story that is as compelling as its color. While not the hardest gemstone, with proper care, peridot can be a lasting and cherished part of any jewelry collection. From its ancient protective qualities in Egyptian lore to its modern status as a symbol of compassion and abundance, peridot continues to captivate gemstone enthusiasts and jewelry buyers alike. Its historical significance, coupled with its distinct gemological properties, ensures that peridot will remain a beloved birthstone for generations to come.