The month of August is uniquely distinguished in the world of gemology by offering a trio of official birthstones: peridot, spinel, and sardonyx. This multiplicity provides those born in the eighth month with a diverse palette of colors, histories, and symbolic meanings to choose from. While peridot is the recognized primary birthstone, its companions spinel and sardonyx are equally celebrated, each with a distinct geological origin, historical journey, and cultural significance. This article delves into the comprehensive world of August's birthstones, examining their formation, gemological properties, historical lore, and the practical considerations for their care and selection.
The Evolution of August's Birthstones
The tradition of associating specific gemstones with birth months has evolved significantly over time. The modern list of birthstones, widely adopted in the United States, was formalized in 1912 by the American Gem Trade Association (AGTA) and Jewelers of America (JA). Initially, peridot was designated as the official August birthstone. However, the list has been periodically updated to reflect changing consumer preferences, market availability, and a desire for greater variety in color and price. Sardonyx is considered the traditional August birthstone, with a history dating back over 4,000 years. In 2016, spinel was added to the official list, providing August-born individuals with a third option. This expansion was driven by the need to offer more choices in terms of color, affordability, and accessibility, ensuring that everyone can find a gem that resonates with their personal style and budget.
Peridot: The Gem of the Sun
Geological Formation and Sources
Peridot is the gem variety of the mineral olivine. Its formation is particularly remarkable, as it can be found in environments of extreme geological conditions. It originates deep within the Earth's mantle and is brought to the surface through volcanic activity. Peridot has also been discovered in meteorites, indicating its extraterrestrial origin. This unique genesis makes peridot one of the few gemstones that can be found both in the Earth's crust and in space. Historically, significant sources include the island of Zabargad (formerly Topazios) in the Red Sea, which was a major source for the ancients and is the origin of the name "topaz." The gem was mistaken for topaz for centuries, and the island's name contributed to this confusion. Today, peridot is mined in various locations, including the United States (Arizona), China, Pakistan, and Myanmar.
Historical Significance and Lore
Peridot has a rich and often misunderstood history. Its name is derived from the Arabic word "faridat," meaning gem. Throughout history, peridot has frequently been confused with other green gemstones, most notably emeralds and topazes. The famous gemstones adorning the Shrine of the Three Holy Kings in Germany’s Cologne Cathedral, long believed to be emeralds, are now known to be peridot. Some historians even speculate that Cleopatra's legendary collection of emeralds may have, in fact, been composed of peridot. The Egyptians revered peridot as "the gem of the sun," believing it possessed protective powers. It was also thought to ward off evil spirits and alleviate anxiety and depression. In medieval times, it was used in jewelry and religious artifacts, valued for its vibrant color and perceived protective qualities.
Gemological Properties
Peridot is distinguished by its unique yellowish-green to greenish-yellow color, which is caused by the presence of iron in its chemical composition. Unlike many other gemstones that derive their color from trace impurities, peridot's hue is an inherent part of its mineral structure. This results in a lively, consistent color that ranges from bright lime to deep olive green. It exhibits a bright, glassy luster and is relatively durable, with a Mohs hardness of 6.5 to 7.0. This hardness makes it suitable for various jewelry applications, though it should be protected from sharp blows and extreme temperature changes. Peridot is a singly refractive gemstone with a refractive index typically ranging from 1.65 to 1.69. It often contains inclusions, which are natural and can help identify the stone. The most prized peridot is a vibrant, medium-dark green with minimal inclusions.
Spinel: The Underappreciated Gem
Geological Formation and Sources
Spinel is a magnesium aluminum oxide mineral that forms in a variety of geological settings, including metamorphic rocks and alluvial deposits. It is often found in the same regions as ruby and sapphire, leading to centuries of confusion. Major sources for fine spinel include Myanmar (Burma), Sri Lanka, and Vietnam. The gem's formation can occur under high-temperature and high-pressure conditions, similar to those that create corundum (ruby and sapphire). Historically, some of the world's most famous "rubies" were later identified as spinel, such as the Black Prince's Ruby and the Timur Ruby, both part of the British Crown Jewels.
Historical Significance and Lore
For centuries, red spinel was mistaken for ruby, a confusion that persisted until the development of modern gemology in the 19th century. This mistaken identity led to spinel being underappreciated, despite its own exceptional beauty and durability. The gem's name is thought to derive from the Greek word "spinella," meaning little thorn, possibly referring to its crystal habit. Spinel gained recognition in its own right as gemological techniques advanced, allowing experts to distinguish it from corundum based on its different physical and optical properties. While it lacks the ancient, widespread lore of peridot, spinel has been valued by royalty and collectors for its vibrant colors and clarity. Its recent addition to the official birthstone list in 2016 reflects a modern renaissance for this historically overlooked gem.
Gemological Properties
Spinel is renowned for its remarkable range of colors. While the most sought-after color is a vivid, ruby-like red, spinel also occurs in a stunning array of hues, including soft pink, fiery orange, rich purple, deep blue, and even jet black. This variety makes it an exceptionally versatile gemstone. Spinel is singly refractive and has a hardness of 8.0 on the Mohs scale, making it very durable and resistant to scratching—ideal for rings and other jewelry that undergoes daily wear. Its refractive index is typically around 1.72. Spinel's color is often described as more saturated and "cleaner" than many other gems, and it does not display the zoning often seen in sapphires. The red variety is particularly prized for its brilliance and similarity to fine ruby, but without the same level of inclusions or price tag.
Sardonyx: The Banded Protector
Geological Formation and Sources
Sardonyx is a variety of onyx, which is a banded chalcedony (a microcrystalline form of quartz). It is characterized by alternating layers of sard (a reddish-brown chalcedony) and onyx (black or dark brown chalcedony). These bands are formed through the deposition of silica in cavities within volcanic rock. The process creates distinct, parallel layers that are often cut en cabochon to highlight the banding. Historically, significant sources included India, Brazil, and Germany. The stone's formation is a slow, geological process that results in a hard, durable gem suitable for carving and engraving.
Historical Significance and Lore
Sardonyx is the oldest of the three August birthstones, with a history spanning over 4,000 years. It was highly valued in ancient Rome, where it was used for cameos and intaglios—engraved gemstones used as seals and amulets. Roman soldiers wore sardonyx rings for protection in battle, believing the stone would grant them courage and strength. Its name comes from the Greek words "sard" (a type of red chalcedony) and "onyx" (meaning nail), referring to its banded appearance. Sardonyx was associated with stability, strength, and protection. It was also believed to enhance communication and bring harmony to relationships. In the Middle Ages, it was used in religious art and jewelry, valued for its symbolic meanings and its ability to be carved into intricate designs.
Gemological Properties
Sardonyx is a form of chalcedony, making it a member of the quartz family. It has a hardness of 6.5 to 7.0 on the Mohs scale, similar to peridot. Its chemical composition is silicon dioxide (SiO₂). The defining characteristic of sardonyx is its banding, with layers of red, brown, and white. The contrast between these bands creates unique patterns in each stone. It is typically cut en cabochon (a smooth, rounded shape) to best display its banding. Sardonyx is not transparent; it is translucent to opaque. Its luster is waxy to vitreous. The stone is durable enough for everyday wear but should be protected from hard impacts that could chip the surface.
Symbolism and Metaphysical Beliefs
Each of the three August birthstones carries its own set of symbolic meanings and metaphysical beliefs, often rooted in ancient traditions and modern crystal healing practices.
- Peridot is widely associated with joy, abundance, and emotional clarity. It is considered a Heart Chakra stone, believed to open the heart to love and healing while releasing negative patterns. Its vibrant green color is linked to growth, renewal, and prosperity. Many believe it alleviates stress and promotes a positive outlook.
- Spinel symbolizes inspiration, energy, and resilience. It is seen as a stone of renewal, helping to restore energy and vitality. Different colors of spinel may be associated with different properties; for example, red spinel is linked to passion and vitality, while blue spinel is associated with calm and communication. It is often used to inspire hope and encouragement during challenging times.
- Sardonyx represents strength, stability, and protection. It is considered a grounding stone that enhances willpower and steadfastness. Its historical use as a protective amulet continues in modern metaphysical beliefs, where it is thought to shield the wearer from negative energies and promote stability in relationships and endeavors.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these gemstones. Their different hardness levels and chemical compositions require specific attention.
- Peridot (Mohs 6.5-7.0) should be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as sudden temperature changes can cause fractures. Store it separately from harder gems to prevent scratches.
- Spinel (Mohs 8.0) is the most durable of the three and can withstand more rigorous cleaning. It is safe to use warm, soapy water, a soft brush, and even an ultrasonic cleaner. However, it should be kept away from extreme heat and sudden temperature changes.
- Sardonyx (Mohs 6.5-7.0) can be cleaned with warm, soapy water and a soft brush. As a form of quartz, it is relatively stable, but the banding can be sensitive to harsh chemicals. Avoid ultrasonic cleaners if the stone has fractures or inclusions. Store it in a soft cloth to prevent scratching.
Conclusion
August's birthstones—peridot, spinel, and sardonyx—offer a remarkable diversity that caters to a wide range of tastes and preferences. Peridot, with its sunlit green hue and ancient history, provides a connection to the Earth's fiery depths. Spinel, in its stunning array of colors, offers a durable and vibrant alternative with a royal pedigree. Sardonyx, the traditional banded stone, carries the weight of millennia of protective symbolism and artistic use. Together, they form a trio that is not only geologically fascinating but also rich in cultural and historical significance. Whether chosen for their beauty, durability, or symbolic meaning, each stone provides a unique and personal connection for those born in the month of August.