The month of August is uniquely endowed with three distinct birthstones: Peridot, Spinel, and Sardonyx. While Peridot is widely recognized as the modern primary birthstone, the inclusion of Spinel and Sardonyx offers a rich palette of colors, histories, and properties for those born in this summer month. The origins of these stones are as varied as their appearances, ranging from the volcanic depths of the Earth to ancient riverbeds, each carrying a legacy of symbolism and lore. The modern list was expanded to provide more choice, acknowledging the historical significance of Sardonyx and the beauty of Spinel, which was often mistaken for ruby throughout history. This guide explores the geological formation, gemological properties, historical significance, and practical care for August's three birthstones, providing a detailed resource for gemstone enthusiasts and collectors.
Peridot: The Olivine Gem of the Sun
Peridot, the gem variety of the mineral olivine, is celebrated for its distinctive and consistent yellowish-green to greenish-yellow hue. This August birthstone is one of the few gemstones that occurs in a single color family, with its shade determined by its iron content. Unlike many other gems, Peridot’s color does not change under different light sources, maintaining its vibrant, grassy green from daylight to incandescent light.
Geological Formation and Sources
Peridot is formed under extreme conditions, crystallizing deep within the Earth's mantle. It is brought to the surface through volcanic activity, often found in hardened lava. In some rare instances, Peridot has been identified in meteorites that have traveled from outer space, making it a truly "out of this world" gem. Historically, the Red Sea island of Topazios was a significant source of Peridot, though the gems mined there were often confused with topaz or emerald. The Shrine of the Three Holy Kings in Germany’s Cologne Cathedral is adorned with 200 carats of gems once believed to be emeralds, which are now known to be Peridot. Other sources for Peridot include Pakistan, Myanmar, and Arizona in the United States.
Gemological Properties
Peridot is a relatively hard and durable gemstone, making it suitable for various types of jewelry. Its chemical composition is (Mg, Fe)₂SiO₄, and it belongs to the olivine group of minerals.
| Property | Description |
|---|---|
| Chemical Formula | (Mg, Fe)₂SiO₄ |
| Crystal System | Orthorhombic |
| Hardness (Mohs Scale) | 6.5 - 7 |
| Refractive Index | 1.65 - 1.69 |
| Luster | Vitreous (glass-like) |
| Color | Yellowish-green to greenish-yellow |
History and Lore
The word "peridot" is derived from the Arabic faridat, meaning "gem." This August birthstone has been valued since ancient times. It was believed to possess protective powers against evil spirits and nightmares. Pliny the Elder, the Roman naturalist, wrote about Peridot, noting its use in jewelry. In medieval times, it was set in gold and worn to ward off melancholy and bring joy. Its association with light has led to its use in church treasures, where it was thought to symbolize the divine light.
Symbolism and Metaphysical Beliefs
Peridot is associated with strength, protection, and prosperity. It is believed to reduce stress and protect its wearer from negativity. Some traditions hold that Peridot can enhance confidence and assertiveness, making it a stone of empowerment. Its vibrant green color is linked to nature, growth, and renewal, aligning it with the heart chakra and promoting emotional balance.
Spinel: The Underrated Beauty Mistaken for Ruby
Spinel is the newest addition to the August birthstone family, officially recognized by the American Gem Trade Association in 2016. For centuries, Spinel was overlooked and often mistaken for ruby or sapphire due to its similar appearance and brilliant colors. However, it is a distinct mineral species with its own unique properties and history.
Geological Formation and Sources
Spinel is a magnesium aluminium oxide with the chemical formula MgAl₂O₄. It forms in metamorphic rocks, particularly in marble, and is often found in alluvial deposits. Historically, some of the world's most famous "rubies" were actually spinels. The "Black Prince's Ruby" in the British Imperial State Crown and the "Timur Ruby" are both large red spinels. Major sources for Spinel include Myanmar (Burma), Sri Lanka, and Tanzania. The gem's ability to form in a wide range of colors, from red and pink to blue and violet, makes it highly sought after by collectors.
Gemological Properties
Spinel is valued for its brilliance, durability, and wide color range. It is a hard gemstone, suitable for everyday wear.
| Property | Description |
|---|---|
| Chemical Formula | MgAl₂O₄ |
| Crystal System | Cubic |
| Hardness (Mohs Scale) | 8 |
| Refractive Index | 1.71 - 1.73 |
| Luster | Vitreous |
| Color | Red, pink, blue, violet, green, gray, black |
History and Lore
Spinel's history is intertwined with that of ruby. For centuries, it was not recognized as a separate gemstone. The name "spinel" is thought to derive from the Latin word spina, meaning "thorn," possibly referring to its crystal habit. Despite being mistaken for ruby, spinel has been prized in its own right in various cultures. In the 19th century, it began to be recognized as a distinct mineral. Its addition as an August birthstone in 2016 was a nod to its beauty and to correct the historical record, offering August-born individuals a vibrant alternative to ruby.
Symbolism and Metaphysical Beliefs
Spinel is associated with revitalizing energy and overcoming lethargy. It is believed to inspire passion and commitment, making it a stone for relationships. Some traditions suggest that Spinel can help in achieving goals and realizing dreams by providing the energy and motivation needed to persevere. Its variety of colors allows it to be linked to different chakras, but it is generally seen as a stone of renewal and rejuvenation.
Sardonyx: The Ancient Stone of Strength and Protection
Sardonyx is the original August birthstone, with a history that dates back over 4,000 years. It is a variety of chalcedony, which is a microcrystalline form of quartz, characterized by its distinctive bands of reddish-brown (sard) and white or black (onyx).
Geological Formation and Sources
Sardonyx forms when layers of sard and onyx grow over each other in volcanic or sedimentary rock. The banding is a result of variations in the silica content during formation. Historically, Sardonyx was sourced from India, but it is also found in Brazil, Germany, and the United States. Its layered structure makes it ideal for carving and cameos, a craft it is famous for.
Gemological Properties
As a variety of quartz, Sardonyx has properties consistent with chalcedony.
| Property | Description |
|---|---|
| Chemical Formula | SiO₂ |
| Crystal System | Trigonal (microcrystalline) |
| Hardness (Mohs Scale) | 6.5 - 7 |
| Refractive Index | 1.53 - 1.54 |
| Luster | Waxy to vitreous |
| Color | Reddish-brown and white/black bands |
History and Lore
Sardonyx was highly prized by ancient Greeks and Romans, who used it for making seals and amulets. It was believed to protect the wearer in battle and to bring victory, courage, and strength. The Roman naturalist Pliny the Elder wrote that Sardonyx could bring about favorable outcomes in legal matters and enhance communication skills. Its use in cameos and intaglios (engraved gems) was widespread, often depicting mythological scenes or portraits. The Gregorian birthstone poem mentions Sardonyx for August, emphasizing its traditional importance.
Symbolism and Metaphysical Beliefs
Sardonyx is a stone of strength and protection. It is believed to instill courage, stamina, and vitality. It is also associated with happiness and clear communication. In some beliefs, Sardonyx is said to help overcome shyness and improve public speaking. Its protective qualities are thought to guard against negativity and misfortune.
Care and Cleaning for August Birthstones
Proper care is essential to maintain the beauty and longevity of these gemstones. Their differing hardness and structural properties require specific cleaning methods.
Peridot Care
Peridot has a hardness of 6.5 to 7 on the Mohs scale, making it moderately durable but susceptible to scratches. It is best to clean Peridot with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as sudden temperature changes can cause fractures. Store Peridot jewelry separately to prevent it from being scratched by harder stones.
Spinel Care
Spinel is a durable gemstone with a hardness of 8 and no cleavage, making it resistant to breaking. It can be safely cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe for Spinel, but it is advisable to avoid them if the stone has surface-reaching fractures. Steam cleaning is also acceptable. Its durability makes it an excellent choice for rings and daily wear.
Sardonyx Care
Sardonyx, like Peridot, has a hardness of 6.5 to 7. It is relatively tough but can be scratched. Clean it with warm, soapy water and a soft brush. Avoid harsh chemicals and ultrasonic cleaners, which could damage the stone or any treatments it may have received. Store Sardonyx jewelry in a soft cloth or separate compartment to protect its polished surface.
Conclusion
August's birthstones—Peridot, Spinel, and Sardonyx—offer a remarkable diversity in color, origin, and history. Peridot, with its vibrant green hue, is a gem of volcanic and extraterrestrial origin, valued for its protective and stress-relieving properties. Spinel, the modern addition, provides a spectrum of brilliant colors and was historically mistaken for ruby, offering a durable and more affordable alternative. Sardonyx, the original August stone, stands as a testament to ancient strength and protection, its banded patterns carved into seals and cameos for millennia. Together, these stones provide those born in August with a choice that can reflect personal style, from the sunny glow of Peridot to the fiery brilliance of Spinel and the classic strength of Sardonyx. Understanding their unique properties and histories enriches the appreciation of these remarkable gems.