The month of August is uniquely distinguished by its association with three distinct birthstones: peridot, sardonyx, and spinel. Among these, peridot stands out as the most recognized and celebrated gem of the summer month. Known for its signature lime-green hue, peridot is a gemstone that captivates with its vibrant color and intriguing origins. Unlike many colored gems that derive their hues from impurities, peridot’s color is an intrinsic property of its chemical composition. This gem, often referred to as the "Evening Emerald" for its ability to maintain its brilliance under artificial light, carries a rich tapestry of history, lore, and scientific fascination. From its formation deep within the Earth's mantle and its occasional extraterrestrial origins to its symbolism of vitality and protection, peridot offers a compelling subject for gemstone enthusiasts and collectors alike. This article explores the multifaceted nature of peridot, examining its geological formation, gemological properties, historical significance, and its esteemed place among the birthstones of August.
History and Lore
Peridot has been a treasured gem for millennia, with a history that spans ancient civilizations and medieval Europe. Its allure was well-known to the ancient Egyptians, who referred to it as the "gem of the sun." They believed the stone held the power of the sun god, Ra, and was a symbol of rebirth and renewal. This association with solar energy and life-giving force made it a powerful amulet against the darkness and evil spirits. The Egyptians mined peridot on the island of Zabargad (also known as St. John's Island) in the Red Sea, a source that produced gems for over 3,500 years. These stones were so highly prized that they were worn by royalty and high priests.
The historical journey of peridot is filled with fascinating tales of misidentification and reverence. Perhaps the most famous example is the collection of 200-carat stones that adorned the Three Holy Kings shrine in Germany’s Cologne Cathedral. For centuries, these gems were believed to be emeralds. It was only later that gemologists identified them as peridot, a testament to the stone's exceptional quality and deep green color, which can easily be mistaken for its more expensive cousin. This was not an isolated incident; Cleopatra’s famed emerald collection was also, in part, composed of peridot. The confusion between the two gems persisted for centuries, underscoring peridot's long-standing reputation as a gem of significant value and beauty.
Throughout the Middle Ages, peridot was imbued with protective and inspirational qualities. It was worn to provide foresight and inspire the wearer, and Romans carried it as a talisman to protect against enchantment and deceit. The stone's association with protection and courage made it a popular choice for amulets and talismans in both ancient and medieval times. In 2005, the reach of peridot's history extended beyond Earth itself when the Stardust space probe returned with comet dust that contained peridot crystals, proving that this gem is not only a product of our planet but also of the cosmos.
In addition to its historical lore, peridot has been formally recognized for its cultural significance. It is the designated gemstone for the 16th wedding anniversary, a tradition that highlights its enduring appeal and symbolic value in celebrating lasting relationships. Its journey from an ancient solar gem to a modern symbol of affection and a celebrated birthstone for August showcases its timeless and universal appeal.
Geological Formation and Sources
Peridot possesses a unique geological origin story that sets it apart from many other gemstones. While most gems are formed in the Earth's crust, peridot is one of the few that originates in the Earth's mantle. The primary mineral that constitutes peridot is olivine, a silicate of iron and magnesium. This mineral forms under extreme heat and pressure deep within the Earth's upper mantle. The gemstones are brought to the surface through tectonic activity and volcanic eruptions. Molten lava acts as a vehicle, carrying fragments of the mantle, including olivine, to the surface. This volcanic origin means that peridot is often found in igneous rocks, and its crystals can sometimes be seen embedded in basalt.
This deep-earth origin gives peridot a special distinction. It is, in essence, a piece of the Earth's interior, a treasure from the planet's molten core brought to light. The process is a dramatic and violent one, but it results in the creation of beautiful green crystals. The chemical composition, which includes iron and magnesium, is directly responsible for the gem's color. The amount and type of iron present determine the specific shade of green, ranging from yellow-green to olive to brown-green. The ferrous iron (FeO) imparts the green color, while ferric iron (Fe2O3) contributes to more yellowish tones.
While peridot is found in various locations around the world, its historical significance is tied to specific sources. The ancient Egyptian mines on the island of Zabargad in the Red Sea are the most famous and were the primary source of peridot for the ancient world. Today, major sources of peridot include Pakistan, which produces large, high-quality crystals in the Kashmir region; Myanmar (Burma); and the United States, particularly Arizona, where peridot is found in basaltic rocks. Other notable sources include Australia, Brazil, China, Kenya, Mexico, Norway, Sri Lanka, and Tanzania. The discovery of peridot in comet dust further expands its known origins to the far reaches of our solar system, making it a truly cosmic gem.
Gemological Properties
Understanding the gemological properties of peridot is essential for appreciating its unique characteristics and for its proper care and identification. As a member of the olivine mineral family, peridot has a distinct set of physical and chemical attributes.
The most defining feature of peridot is its color. It is best known for its brilliant lime-green color, a characteristic that is not due to chemical impurities but is an inherent part of its composition. The color is derived from the presence of iron within its chemical structure. Peridot is one of the few gemstones that appears in only a single color family—green—in various intensities and shades. It can range from a light, yellowish-green to a deep, olive green, depending on the amount of iron present. A unique quality of peridot is its consistent appearance in both natural and artificial light. It does not exhibit the pleochroism (showing different colors from different angles) common in many other gems, which is why it is sometimes called the "Evening Emerald." It shines with the same verdant brilliance day or night.
In terms of hardness, peridot has a rating of 6.5 to 7.0 on the Mohs scale. This makes it a moderately hard gem, suitable for jewelry, but it is softer than many other popular stones like sapphire, ruby, and diamond. Consequently, peridot is more susceptible to scratching and abrasion if worn daily without care. Its durability is also affected by its cleavage, which is poor in two directions. This means that a sharp blow could cause the gem to crack or cleave, so protective settings are recommended for rings and bracelets.
The chemical composition of peridot is (Mg, Fe)₂SiO₄. It is a solid solution series between the magnesium-rich forsterite and the iron-rich fayalite. The refractive index of peridot typically falls between 1.65 and 1.69. While it is most often found in smaller sizes, large peridots are rare and highly valued. The gem is typically faceted to maximize its brilliance, but it can also be found in cabochon cuts, especially when inclusions are present. Its specific gravity ranges from 3.27 to 4.37, another property that helps in its identification.
| Property | Description |
|---|---|
| Mineral Family | Olivine |
| Chemical Formula | (Mg, Fe)₂SiO₄ |
| Color | Green, from yellow-green to olive to brown-green |
| Hardness (Mohs Scale) | 6.5 - 7.0 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.65 - 1.69 |
| Origin | Earth's mantle, brought to surface by volcanic activity |
Symbolism and Metaphysical Beliefs
Peridot is steeped in symbolism and has been attributed with a wide range of metaphysical powers throughout history. Its vibrant green color, reminiscent of nature and springtime, has made it a symbol of life, growth, and renewal. Ancient cultures saw peridot as a gem that could harness the power of the sun, bringing warmth, light, and abundance to its wearer. The Egyptians’ belief in it as the "gem of the sun" highlights its connection to vitality and rebirth.
Beyond its solar associations, peridot is also considered a stone of compassion and healing. In medieval times, it was believed to have the power to banish darkness and evil spirits, and to heal and purify the heart. It was thought to inspire eloquence and to open the heart to new experiences and relationships. Modern metaphysical beliefs continue this tradition, suggesting that peridot can alleviate feelings of jealousy, resentment, and spite, replacing them with a sense of inner peace and positive emotional states.
As the birthstone for August, peridot is also rumored to strengthen friendships and harmony. It is seen as a gem that spreads good vibes and encourages a joyful, optimistic outlook on life. Its association with vitality, growth, and prosperity makes it a popular choice for those seeking to attract success and good fortune. Whether worn as jewelry or kept as a talisman, peridot is believed to be a powerful tool for enhancing well-being and connecting with the vibrant, life-affirming energies of the natural world.
Care and Cleaning
Due to its moderate hardness and poor cleavage, peridot requires careful handling and cleaning to maintain its beauty and integrity. With a Mohs hardness rating of 6.5 to 7.0, it is softer than many other gemstones and can be scratched by harder materials. When storing peridot jewelry, it is crucial to keep it separate from other stones like diamonds, sapphires, and rubies to prevent accidental abrasion. Ideally, it should be stored in a soft-lined box or a separate pouch.
Cleaning peridot is a straightforward process. The recommended method is to use a soft-bristle brush (such as a toothbrush) with a mixture of mild dish soap and warm water. Gently scrub the gemstone and its setting, then rinse thoroughly with warm water to remove any soap residue. It is important to dry the jewelry completely with a soft, lint-free cloth before storing it.
Peridot should not be subjected to harsh chemicals, including household cleaners, bleach, or acids, as these can damage the stone's surface. It is also advisable to remove peridot jewelry before engaging in activities that could cause impact or exposure to abrasive materials, such as gardening, sports, or heavy manual work. Ultrasonic and steam cleaners are generally not recommended for peridot, especially if the stone has been fracture-filled or has significant inclusions, as the vibrations and high heat can cause damage. By following these simple care instructions, the radiant green beauty of peridot can be preserved for generations.
Other Birthstones for August
While peridot is the most famous and widely recognized birthstone for August, the month is also associated with two other gems: sardonyx and spinel. These stones offer a diverse palette of colors and histories for those born in the last full month of summer.
Sardonyx is a variety of chalcedony, which is a cryptocrystalline form of quartz. It is characterized by its distinctive banding, which consists of alternating layers of reddish-brown sard and white or black onyx. This banded appearance gives it a unique, often rustic, aesthetic. Sardonyx has a long history as a stone of protection and courage. Ancient Greeks and Romans famously wore sardonyx talismans and amulets into battle, believing the stone would grant them bravery and shield them from harm. Its name is derived from the Greek words "sard" (reddish-brown) and "onyx" (veined stone). It remains a popular choice for signet rings and cameos due to its ability to be carved and its contrasting layers.
Spinel was added to the list of August birthstones more recently, providing a modern alternative with its own rich history. Spinel occurs in a breathtaking array of colors, including vibrant reds, deep blues, pinks, purples, and even black. The red varieties of spinel have often been mistaken for rubies throughout history. The "Black Prince's Ruby," one of the British Crown Jewels, is a famous example of a large red spinel that was long thought to be a ruby. Spinel is known for its excellent hardness (8.0 on the Mohs scale) and brilliance, making it a durable and beautiful gemstone for all types of jewelry. Its addition to the August birthstone list offers greater choice and flexibility for individuals born in that month.
Conclusion
Peridot is a gemstone of remarkable character, distinguished by its unique origin, its singular green color, and its storied past. From its formation deep within the Earth's mantle to its discovery in interplanetary dust, this August birthstone embodies a connection to both the planet and the cosmos. Its brilliant lime-green hue, a direct result of its iron and magnesium composition, has captivated humanity for thousands of years, earning it a place among the most revered gems of antiquity. Whether serving as a symbol of the sun in ancient Egypt, a protective talisman in Rome, or a misunderstood emerald in a medieval cathedral, peridot has consistently proven its value and allure. While it requires some care due to its moderate hardness, its vibrant color and positive symbolism make it a cherished gem for jewelry and a fitting tribute to those born in the heart of summer. Alongside its fellow August birthstones, sardonyx and spinel, peridot completes a diverse and fascinating trio, offering a unique blend of scientific wonder, historical depth, and enduring beauty.