Introduction
Peridot, the gem-quality variety of the mineral olivine, stands as the primary birthstone for the month of August. Distinguished by its signature lime-green hue, this gem possesses a geological history that spans billions of years and a human history of appreciation that reaches back to ancient civilizations. Unlike many other gemstones that occur in a spectrum of colors, peridot is celebrated for appearing in only one color family—shades of green—though the intensity and undertone can vary significantly. Its allure lies not only in its vibrant color but also in its unique formation, occurring in the hardened lava of Earth’s mantle and, remarkably, in meteorites that have traveled from outer space.
While peridot is the dominant modern birthstone for August, it shares this designation with two other historically significant gems: spinel and sardonyx. These three stones offer those born in August a variety of choices, each with its own distinct character, history, and symbolism. This article will explore the rich tapestry of peridot, detailing its geological origins, its journey through history, its specific gemological properties, and the symbolism it has carried through the ages. We will also examine the roles of its companion birthstones, spinel and sardonyx, providing a comprehensive guide to the gems of August.
History and Lore
The history of peridot is as vibrant as its color, with records of its use dating back over 3,500 years. The earliest known source of peridot was the Red Sea island of Zabargad (also known as Topazios). This island was the origin of many gems that were historically mistaken for other green stones, most notably emeralds and topazes. The island's name, "Topazios," is a testament to this confusion, as it was believed to be the source of topaz, yet it produced peridot.
Ancient Egyptians held peridot in particularly high regard, referring to it as the "gem of the sun." They believed the stone possessed protective powers, capable of warding off nightmares and bringing happiness, strength, and success to its wearer. This reverence made peridot a popular gem for jewelry and talismans in ancient Egyptian culture.
The confusion between peridot and other green gemstones continued for centuries. In medieval Europe, a significant collection of gems adorning the Shrine of the Three Holy Kings in Germany’s Cologne Cathedral—totaling 200 carats—were long believed to be emeralds. Modern analysis has confirmed that these gems are, in fact, peridot. This misidentification was not limited to ecclesiastical treasures; some historians speculate that Cleopatra’s famous collection of emeralds may have actually been composed of peridot. This enduring confusion underscores peridot's visual appeal and its capacity to rival the beauty of more traditionally prized green gems.
The name "peridot" itself is believed to derive from the Arabic word "faridat," meaning gem. This etymology points to the gem's long-standing value in Middle Eastern cultures. Throughout history, peridot has been valued not just for its beauty but for the cultural significance it carried, often associated with light, the sun, and divine favor.
Geological Formation and Sources
Peridot's formation process is extraordinary, setting it apart from many other gemstones. As the gem variety of the mineral olivine, peridot is formed under extreme conditions deep within the Earth's mantle. The primary source of peridot found on the Earth's surface is from magma that cooled to form basalt, which carries the crystals up from the mantle. This volcanic origin explains why peridot is often found in lava flows and other volcanic rock formations.
Perhaps even more fascinating is peridot's extraterrestrial origin. Peridot has been discovered in meteorites, specifically pallasite meteorites, which are stony-iron meteorites. This confirms that the mineral olivine is not exclusive to Earth and can form in the harsh conditions of outer space. The discovery of peridot in these cosmic travelers adds a layer of mystique to the gem, connecting it to the vastness of the universe.
The historical source of peridot, the Red Sea island of Zabargad, remains a significant location in the gem's lore. While mining operations have occurred at this site for millennia, the peridot found there is known for its distinct olive-green color. Today, peridot is also mined in other parts of the world, including Pakistan, Myanmar, and the United States (specifically Arizona). The gem's formation in the mantle and its appearance in meteorites make it a subject of great interest for geologists and gemologists alike.
Gemological Properties
Peridot possesses a unique set of physical and chemical characteristics that define it in the world of gemology. Understanding these properties is crucial for identification, valuation, and proper care.
Chemical Composition and Color
Peridot is a magnesium iron silicate with the chemical formula (Mg, Fe)₂SiO₄. Its signature green color is due to the presence of iron. The shade of green can range from yellowish-green to olive to brownish-green, depending on the specific iron content within the crystal structure. The most desirable color is typically a rich, vibrant lime-green.
Hardness and Durability
On the Mohs scale of hardness, peridot ranks between 6.5 and 7. While this makes it a relatively durable gemstone suitable for everyday jewelry, it is softer than stones like sapphire or diamond. This means that peridot can be susceptible to scratches and abrasions if not handled with care, particularly when worn in rings or bracelets that are exposed to daily wear.
Other Properties
Peridot is a doubly refractive gemstone, meaning light splits into two rays as it passes through the crystal. It has a refractive index that typically falls between 1.65 and 1.69. The crystal structure is orthorhombic. Peridot does not have cleavage, which is a tendency to break along flat planes, making it less prone to chipping compared to some other gemstones. However, its hardness requires that it be protected from harder materials.
| Gemological Property | Peridot Value |
|---|---|
| Mineral | Olivine |
| Chemical Formula | (Mg, Fe)₂SiO₄ |
| Hardness (Mohs Scale) | 6.5 - 7 |
| Crystal System | Orthorhombic |
| Refractive Index | 1.65 - 1.69 |
| Typical Colors | Yellowish-green to olive-green |
The Companion August Birthstones: Spinel and Sardonyx
While peridot is the most well-known August birthstone, the American Gem Trade Association (AGTA) and Jewelers of America (JA) recognize two other stones for this month: spinel and sardonyx. These gems provide a range of colors and historical depth for those born in August.
Spinel: The Underappreciated Beauty
Spinel has often lived in the shadow of other gemstones, most notably ruby. For centuries, red spinel was mistaken for ruby, with some of the world's most famous "rubies" being identified as spinel. The "Black Prince's Ruby" in the British Imperial State Crown is a prominent example of a large red spinel.
Historically undervalued due to this confusion, spinel is now appreciated as a beautiful and durable gemstone in its own right. It occurs in a wide variety of colors, including vibrant reds, pinks, oranges, and blues, and even black. Spinel was added as an official August birthstone in 2016, giving consumers more options for color and affordability. Symbolically, spinel is associated with renewal, inspiration, and vitality. It is considered a high-energy stone that can help restore energy and inspire hope.
Sardonyx: The Original August Birthstone
Sardonyx is the original and most ancient of the August birthstones, with a history that dates back more than 4,000 years. It is a variety of onyx, characterized by its distinctive bands of reddish-brown (sard) and black or white (onyx). This banded chalcedony was a popular choice for cameos and intaglios in ancient Rome and Greece, where it was valued for its ability to be carved into intricate designs.
Sardonyx is deeply associated with strength, courage, and protection. Ancient warriors would often wear sardonyx amulets into battle, believing the stone would grant them courage and shield them from harm. Its earthy, grounding energy is said to promote stable relationships and provide support during challenging times. As the traditional birthstone for August, sardonyx offers a connection to ancient history and symbolism that is both profound and enduring.
Symbolism and Metaphysical Beliefs
Across cultures and through the centuries, peridot has been imbued with a rich array of symbolic meanings and metaphysical beliefs. Its association with the sun has made it a symbol of light, warmth, and positivity.
Ancient Egyptians believed peridot could ward off evil spirits and protect its wearer from nightmares, bringing happiness and strength. In modern crystal healing practices, peridot is strongly linked to the heart chakra, the energy center associated with love, compassion, and emotional balance. It is believed to help release negative patterns and open the heart to new love and joy.
The stone's symbolism extends to concepts of strength and growth. Its vibrant green color, reminiscent of new life and nature, connects it to themes of renewal and prosperity. Peridot is also thought to bring good fortune and aid in the achievement of one's goals, making it a popular talisman for success and abundance.
Spinel, with its energetic properties, is believed to restore energy and inspire hope during difficult times. It is a stone of renewal and vitality, encouraging perseverance and a positive outlook. Sardonyx, on the other hand, is a stone of stability and protection. Its grounding energy is said to foster courage, strength, and steadfastness in relationships and personal endeavors.
Care and Cleaning
The durability of a gemstone determines the best methods for its care and cleaning. Given their respective hardness and chemical properties, the August birthstones require specific handling to maintain their beauty.
Peridot Care
With a hardness of 6.5 to 7 on the Mohs scale, peridot is durable enough for most jewelry but requires care to avoid scratches. It is best to clean peridot using warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe for peridot, but steam cleaning should be avoided as the heat and sudden temperature changes can potentially damage the stone. It is also advisable to store peridot jewelry separately from other gems and metals to prevent scratching.
Spinel Care
Spinel is a more durable choice, ranking an 8 on the Mohs scale. This makes it resistant to scratching and suitable for all types of jewelry. Spinel can be safely cleaned with warm, soapy water and a soft brush. It is also generally safe to use ultrasonic and steam cleaners, making maintenance relatively straightforward.
Sardonyx Care
As a variety of chalcedony (quartz), sardonyx has a hardness of 6.5 to 7, similar to peridot. It is relatively tough and can be used in jewelry that may be subject to some wear. Cleaning sardonyx is simple: use warm, soapy water and a soft brush. It is best to avoid harsh chemicals and extreme temperatures. Ultrasonic cleaners are usually safe, but steam cleaning is not recommended.
Conclusion
The birthstones of August offer a remarkable diversity of color, history, and meaning. Peridot stands out with its singular, vibrant green hue, a product of both terrestrial volcanic activity and extraterrestrial origins. Its journey from the ancient mines of Zabargad to modern jewelry boxes is filled with lore about sun worship, protection, and prosperity. Spinel provides a spectrum of brilliant colors and has finally shed its historical confusion with ruby to be recognized for its own unique beauty and energetic properties. Sardonyx, the original August stone, connects the modern wearer to millennia of history through its distinctive bands and its ancient symbolism of strength and courage. Together, these three gems provide a rich palette for those born in August, allowing them to choose a stone that resonates with their personal style and spiritual connection.