Peridot and spinel are the two principal birthstones for the month of August, each offering a distinct spectrum of color, history, and symbolic meaning. While peridot is celebrated for its vibrant olive-green hue and ancient origins, spinel is prized for its remarkable durability and occurrence in a wide array of colors, including the coveted reds and blues that mimic other precious gems. Together, they provide those born in August with a diverse palette of choices, from the protective green of peridot to the resilient and versatile nature of spinel. This article explores the geological formation, gemological properties, historical lore, and modern significance of these two captivating August birthstones.
History and Lore
The historical narratives of peridot and spinel are deeply intertwined with human civilization, though their paths to recognition as August birthstones have followed different timelines.
Peridot’s history is one of ancient reverence. Often mistaken for emeralds by ancient civilizations, peridot was mined and valued in antiquity. One of its most significant historical sources was the island of Zabargad (St. John’s Island) in the Red Sea, which supplied peridot to Egyptian and Roman jewelers. The gem was particularly associated with the Egyptians, who called it the "gem of the sun." It was believed to possess protective qualities, warding off evil spirits and nightmares. This lore of protection is a recurring theme in peridot’s history, extending into medieval times when it was thought to guard against the night terrors of witches and demons. Its use in religious artifacts and royal jewelry underscores its long-standing cultural importance.
Spinel, on the other hand, has a more complex history, often overshadowed by its more famous look-alikes. For centuries, large red spinels were mistaken for rubies. The most famous example is the "Black Prince’s Ruby," a massive red spinel that has been part of the British Crown Jewels since the 14th century. Similarly, the "Timur Ruby," another large red spinel, was long misidentified as a ruby. This historical confusion is a testament to spinel’s visual similarity to ruby and sapphire, but it also highlights its own inherent value. Spinel was not formally recognized as a distinct gemstone until the late 18th century, but its durability and beauty have been appreciated for millennia. Its inclusion as a modern birthstone for August, as noted in the sources, is a relatively recent development, aimed at providing a more durable and color-diverse option for August-born individuals.
The modern birthstone list, which includes both peridot and spinel for August, reflects a blend of tradition and modern gemological understanding. Traditional lists, such as the one dating back to the 19th century, often featured sardonyx as the primary August birthstone. Sardonyx is a banded variety of chalcedony, valued historically for its use in cameos and beads. However, the contemporary list has evolved, with peridot maintaining its position and spinel being added as a modern option. This evolution allows for greater personal choice, aligning with the practice of jewelers adding options to the modern birthstone chart to suit contemporary tastes and market availability.
Geological Formation and Sources
The origins of peridot and spinel are as distinct as their appearances, arising from different geological environments and found in specific regions around the world.
Peridot: A Gem from the Mantle
Peridot is the gem variety of the mineral olivine, with a chemical formula of (Mg, Fe)₂SiO₄. Unlike many gemstones that form in the Earth's crust, peridot is unique in that it can form deep within the Earth's mantle and be brought to the surface through volcanic activity. It is found in peridotite, a rock that is a major component of the upper mantle. This deep-earth origin explains why peridot crystals are sometimes found in volcanic rocks, such as basalt, or in certain types of meteorites, known as pallasite meteorites, which contain olivine crystals.
Key historical sources for peridot include the island of Zabargad in the Red Sea, which was a major source for ancient Egyptian and Roman jewelry. In the modern era, significant peridot deposits have been found in the United States, particularly in Arizona's San Carlos Apache Indian Reservation, which is a leading source of commercial peridot. Other important sources include Pakistan, Myanmar, and China. The gem's color can vary from yellowish-green to olive green, depending on the iron content, with the most prized colors being a rich, pure olive green.
Spinel: A Mineral of Diverse Environments
Spinel is a magnesium aluminum oxide with the formula MgAl₂O₄. It forms in a variety of geological settings, most commonly in metamorphic rocks, such as marbles and schists, and in alluvial deposits. The gem's formation often occurs in contact zones where rocks have been altered by heat and pressure, allowing for the growth of spinel crystals.
Spinel is mined in several countries, with some of the most historically significant sources being in Southeast Asia. Myanmar (Burma) has been a renowned source for high-quality red and blue spinels, particularly from the Mogok region. Sri Lanka is another important source, known for producing a wide range of spinel colors. Additional sources include Afghanistan, Vietnam, and Tajikistan. The gem's ability to form in a wide array of colors, including red, blue, pink, purple, and black, is due to trace elements like iron, chromium, and cobalt incorporated into its crystal structure during formation.
Gemological Properties
Understanding the physical and chemical properties of peridot and spinel is essential for appreciating their value, durability, and suitability for jewelry.
Peridot Properties
- Chemical Composition: (Mg, Fe)₂SiO₄ (Olivine)
- Crystal System: Orthorhombic
- Hardness: 6.5 to 7 on the Mohs scale
- Refractive Index: 1.642 to 1.690
- Specific Gravity: 3.27 to 4.37
- Cleavage: Poor/Indistinct
- Color Range: Olive green to yellowish-green; the iron content determines the exact shade.
- Transparency: Transparent to translucent
Peridot’s hardness of 6.5 to 7 makes it suitable for most types of jewelry, but it requires some care to avoid scratching. Its poor cleavage means it is less prone to breaking along planes when struck, which is a beneficial property for gemstones used in rings and bracelets. The most valued peridot color is a pure, intense olive green without strong yellow or brown undertones.
Spinel Properties
- Chemical Composition: MgAl₂O₄
- Crystal System: Cubic
- Hardness: 8 on the Mohs scale
- Refractive Index: 1.712 to 1.762
- Specific Gravity: 3.57 to 3.70
- Cleavage: Indistinct
- Color Range: Wide variety, including red, blue, pink, purple, black, and colorless.
- Transparency: Transparent to opaque
Spinel’s hardness of 8 on the Mohs scale makes it exceptionally durable, suitable for all types of jewelry, including engagement rings. Its toughness and resistance to scratching are superior to many other gemstones. The lack of cleavage planes enhances its durability further. Spinel’s refractive index and specific gravity are generally higher than those of peridot, which can be a distinguishing factor for gemologists. The gem’s color variety is one of its most attractive features, allowing it to mimic other precious stones while maintaining its own unique identity.
Comparative Durability for Jewelry
The following table compares the hardness and suitability of peridot and spinel for different jewelry applications:
| Gemstone | Hardness (Mohs) | Suitability for Jewelry | Notes |
|---|---|---|---|
| Peridot | 6.5 - 7 | Good for most jewelry, but requires care in rings and bracelets. | Prone to scratching if worn daily without protection. Best in protected settings like pendants or earrings. |
| Spinel | 8 | Excellent for all jewelry types, including engagement rings. | Highly durable and resistant to scratching and abrasion. Can withstand decades of wear. |
| Sardonyx | 6.5 - 7 | Good for beads, cabochons, and cameos. | A banded chalcedony, less durable for delicate settings. |
Both peridot and spinel are durable enough for everyday wear, but spinel’s higher hardness gives it an edge for jewelry pieces that may be subject to more impact, such as rings and bracelets.
Symbolism and Metaphysical Beliefs
The symbolic meanings and metaphysical beliefs associated with peridot and spinel are rich and varied, reflecting their historical and cultural significance.
Peridot: The Stone of Protection and Renewal
Peridot is widely regarded as a stone of protection, a belief that dates back to ancient times. It was thought to ward off evil spirits, nightmares, and negative energies. In modern crystal healing, peridot is associated with strength, good fortune, and peace. It is believed to attract abundance, prosperity, and success, making it a popular stone for those seeking to enhance their personal power and confidence. Peridot is also linked to the heart chakra, promoting emotional balance, forgiveness, and compassion. Its vibrant green color is often connected to nature, growth, and renewal, symbolizing new beginnings and the vitality of life.
Spinel: The Stone of Renewal and Resilience
Spinel is often associated with renewal, revitalization, and the rejuvenation of spirit and body. Its wide range of colors allows for different symbolic associations; for example, red spinel is linked to passion and energy, while blue spinel is connected to calm and communication. Historically, spinel was believed to have protective properties, especially when worn as an amulet. In contemporary metaphysical practices, spinel is considered a stone that can help overcome lethargy, inspire new ideas, and provide mental clarity. Its durability is sometimes metaphorically linked to emotional resilience and the ability to endure challenges. As a modern birthstone, spinel symbolizes versatility and strength, offering August-born individuals a gem that is both beautiful and robust.
Sardonyx: The Stone of Courage and Communication
Although less commonly associated with August in modern lists, sardonyx holds historical significance. It is a banded stone that has been used for centuries in cameos and amulets. In ancient Rome, sardonyx was believed to bring courage and protection to warriors. It was also associated with clear communication and eloquence, often worn by orators and leaders. The layered bands of sardonyx were thought to represent the layers of one’s character, promoting integrity and steadfastness. While its use as a primary birthstone has diminished, it remains a stone of historical and artistic value.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone jewelry. The specific care requirements for peridot and spinel are dictated by their physical properties.
Caring for Peridot
Due to its moderate hardness (6.5-7) and poor cleavage, peridot requires careful handling. It is susceptible to scratching if stored with harder gems like diamonds, sapphires, or rubies. To clean peridot, use warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as sudden temperature changes can cause damage. It is also advisable to remove peridot jewelry before engaging in physical activities or household chores to prevent impact and exposure to harsh chemicals, which can dull its surface or damage the stone.
Caring for Spinel
Spinel’s high hardness (8) and toughness make it one of the most durable gemstones. It is resistant to scratching and can withstand daily wear with minimal risk of damage. Cleaning spinel is straightforward: use warm, soapy water and a soft brush. Spinel is generally safe for ultrasonic cleaning, but it is always best to consult with a professional jeweler before using any mechanical cleaning methods. While spinel is durable, it is still recommended to store it separately from other jewelry to prevent abrasion from harder gems.
General Jewelry Care Tips
- Storage: Store gemstones in separate compartments or soft cloth pouches to prevent scratching.
- Avoid Chemicals: Remove jewelry before applying lotions, perfumes, or cleaning agents, as these can degrade the gemstone’s surface over time.
- Regular Inspections: Have jewelry professionally inspected periodically to ensure settings are secure and stones are not loose.
- Professional Cleaning: For deep cleaning or repairs, always seek the assistance of a qualified jeweler.
Conclusion
Peridot and spinel, the two modern birthstones for August, offer a compelling contrast in color, history, and character. Peridot, with its ancient origins and protective lore, provides a vibrant green option that has been cherished for millennia. Spinel, with its exceptional durability and versatile color range, offers a modern, resilient alternative that can mimic the appearance of other precious gems. Both stones possess unique gemological properties that make them suitable for a variety of jewelry styles, from delicate pendants to robust engagement rings. Their inclusion in the August birthstone list reflects the evolving nature of gemological tradition, allowing individuals to choose a stone that resonates with their personal style and the symbolic meanings they hold dear. Whether drawn to the protective green of peridot or the enduring versatility of spinel, those born in August have access to gemstones of remarkable beauty and significance.