August is a unique month in the world of birthstones, celebrated with not one, but three distinct and beautiful gemstones: sardonyx, peridot, and spinel. Each gem boasts a rich history, unique physical properties, and symbolic meaning, offering a diverse range of options for those born in the eighth month of the year. This article will delve into the origins, characteristics, and significance of these three August birthstones, providing a comprehensive overview for enthusiasts, buyers, and students of gemology.
History and Lore
Historically, sardonyx held the sole designation as the August birthstone. Its use dates back to ancient times, particularly within the Roman Empire, where it was favored for creating seals and signet rings. The material’s smooth surface prevented hot wax from adhering, making it ideal for this purpose. For millennia, the distinctive banded patterns of sardonyx made it a popular choice for carving cameos and intaglios, showcasing artistry and craftsmanship.
The landscape of birthstone recognition shifted in the early 20th century. In 1912, the National Association of Jewelers, now known as Jewelers of America, officially added peridot as a secondary birthstone for August. This decision broadened the options available to those born in the month. Further expansion occurred in 2016 when both Jewelers of America and the American Gem Trade Association jointly recognized spinel as a third August birthstone. This addition aimed to increase awareness and appreciation for spinel, a gem often confused with ruby due to its similar appearance.
Geological Formation and Sources
Sardonyx is a variety of chalcedony, a cryptocrystalline form of quartz. It is formed through the layering of sard, a reddish-brown variety, and onyx, typically white or black. This banding creates the distinctive appearance of the gemstone.
Peridot, always green in color, is formed in solidified lava and is brought to the surface through volcanic activity. While relatively common in smaller sizes, larger, high-quality peridot stones are considered valuable finds.
Spinel’s origins are diverse. A significant discovery in 2007 in Tanzania revealed spinel in pinkish and orangy-red hues, captivating gem collectors. Tanzanian mines also produce spinel in purple and blue shades. The gem’s formation often occurs in metamorphic rocks.
Gemological Properties
Each of the August birthstones possesses unique gemological properties that contribute to its distinct character.
Sardonyx: As a form of chalcedony, sardonyx does not have a specific chemical formula beyond that of silicon dioxide (SiO2). Its appearance is defined by the alternating bands of sard and onyx.
Peridot: Peridot’s chemical formula is (Mg, Fe)2SiO4, indicating it is a magnesium iron silicate. It typically rates 6.5 to 7 on the Mohs hardness scale, making it relatively soft compared to other gemstones. Its color ranges from lime to olive green, dependent on its source.
Spinel: Spinel has a chemical formula of MgAl2O4, a magnesium aluminum oxide. It is a durable gemstone, registering an 8 on the Mohs hardness scale, making it suitable for everyday wear, including in rings. Spinel exhibits a broad color palette, including reds, pinks, blues, purples, oranges, and yellows. Some colors can fade with prolonged exposure to high heat.
The following table summarizes the key gemological properties:
| Gemstone | Chemical Formula | Mohs Hardness | Color |
|---|---|---|---|
| Sardonyx | SiO2 | N/A (Chalcedony) | Banded reddish-brown and white/black |
| Peridot | (Mg, Fe)2SiO4 | 6.5 - 7 | Lime to olive green |
| Spinel | MgAl2O4 | 8 | Red, pink, blue, purple, orange, yellow |
Symbolism and Metaphysical Beliefs
Throughout history, each of these gemstones has been attributed with specific meanings and powers.
Sardonyx was historically believed to offer courage and protection. Its banded layers were thought to represent strength and stability.
Peridot has long been associated with protection, particularly against nighttime evil spirits. Ancient cultures linked its lively green color to the sun, believing it could ward off darkness. It is also credited with bringing good health and peace.
Spinel is often seen as a stone of revitalization, said to refresh and rejuvenate the wearer. It is believed to help overcome stress and improve self-esteem, offering hope and encouragement.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of these August birthstones.
Sardonyx, being a form of chalcedony, requires gentle handling. Avoid harsh chemicals and abrasive cleaners. A soft cloth is sufficient for routine cleaning.
Peridot, with its relatively lower hardness, is susceptible to scratches and damage. It should be cleaned with a soft cloth and mild soapy water. Avoid ultrasonic and steam cleaners, as well as sudden temperature changes. It is advisable to hold peridot jewelry by the metal setting when cleaning to prevent skin oils from dulling the stone. Professional cleaning is recommended annually.
Spinel, being more durable, can generally withstand ultrasonic and steam cleaning. However, the presence of fractures within the stone may pose a problem. Warm soapy water is always a safe alternative. Spinel is stable when exposed to light and most chemicals, but high heat can cause some colors to fade.
Conclusion
The August birthstones – sardonyx, peridot, and spinel – represent a captivating blend of history, beauty, and symbolism. From the ancient Roman use of sardonyx to the modern appreciation of spinel’s vibrant colors and the enduring allure of peridot’s green hues, these gemstones offer a rich tapestry of choices for those born in August. Understanding their unique properties and origins allows for a deeper appreciation of these remarkable gifts from the earth.