August boasts not one, but three recognized birthstones: peridot, sardonyx, and spinel. While peridot and sardonyx have historical precedence, spinel has recently gained prominence, officially recognized as an August birthstone by the American Gem Trade Association (AGTA). Each stone possesses unique characteristics, historical significance, and symbolic meanings, offering a diverse range of options for those born in the eighth month of the year. This article will delve into the geological origins, gemological properties, historical lore, and contemporary uses of these three captivating gemstones.
History and Lore
Sardonyx holds the longest-standing association with August, utilized for millennia in jewelry and ornamental carvings. Ancient Romans favored sardonyx for seals and signet rings, appreciating its property of preventing hot wax from adhering to its surface. The banded structure of sardonyx, composed of sard (brownish-red) and onyx (white or black chalcedony), made it a popular material for cameos and intaglios, showcasing intricate designs.
Peridot’s history is equally rich, with early finds originating in Egypt. Legend attributes peridot to Queen Cleopatra VII, who adorned herself with these vibrant green gems. In ancient Egypt, peridot was believed to possess healing properties and was often set in gold. The Hawaiian people also hold peridot in high regard, considering the gem to be the solidified tears of Pele, the volcanic goddess.
Spinel, while historically sometimes mistaken for ruby or sapphire due to its similar appearance, has a history of its own. Though not as extensively documented as peridot or sardonyx in ancient times, spinel has been treasured for centuries. A significant discovery in Tanzania in 2007 brought renewed attention to spinel, revealing stones in a variety of captivating colors, including pinkish-red, orange, purple, and blue.
Geological Formation and Sources
Peridot is formed in the Earth’s mantle and brought to the surface through volcanic activity. Notable sources include Egypt, where it was first discovered, as well as Hawaii, Myanmar (Burma), and Vietnam. Vietnamese peridot, discovered in the 1990s, is particularly valued for its diverse shades of green, while Burmese peridot is known for its large size and rich color.
Sardonyx, a variety of chalcedony, is formed through the layering of sard and onyx within silica-rich volcanic lava. Primary sources include India, but it is also found in Brazil, Uruguay, the United States, and Germany.
Spinel forms in metamorphic rocks and alluvial deposits. Historically, significant spinel deposits were found alongside rubies and sapphires in Myanmar. More recently, Tanzania has emerged as a prominent source, yielding spinels in a remarkable range of colors. Spinel can also be found in Sri Lanka, Thailand, and Vietnam.
Gemological Properties
Peridot is known for its distinctive olive-green to yellowish-green color, a result of its iron content. The intensity of the color correlates with the amount of iron present; more iron leads to a more vibrant hue and increased value. Peridot typically exhibits a crystal-like appearance.
Sardonyx is characterized by its banded structure, featuring alternating layers of reddish-brown to brown sard and white or black onyx. It has a more stone-like appearance compared to the crystalline structure of peridot.
Spinel boasts a hardness of 8 on the Mohs scale, making it a durable gemstone suitable for everyday wear. It exhibits excellent brilliance and sparkle, a quality that has endeared it to gem collectors and jewelers. Spinel occurs in a wide spectrum of colors, including red, orange, yellow, blue, green, and purple, with specific color variations receiving industry-specific names such as rubicelle (yellow-orange), almandine (purple), sapphirine (blue), and chlorospinel (green).
The following table summarizes key gemological properties:
| Gemstone | Chemical Composition | Color | Hardness (Mohs) | Luster | Transparency |
|---|---|---|---|---|---|
| Peridot | Olivine (Mg,Fe)₂SiO₄ | Olive Green to Yellowish-Green | 6.5 - 7 | Vitreous | Transparent to Translucent |
| Sardonyx | SiO₂ (Chalcedony) | Banded Reddish-Brown & White/Black | 6.5 - 7 | Waxy | Translucent |
| Spinel | MgAl₂O₄ | Various (Red, Blue, Green, etc.) | 8 | Vitreous | Transparent to Opaque |
Symbolism and Metaphysical Beliefs
Peridot is often associated with good health, peace, and harmony. It is considered the “gem of compassion,” believed to bring renewal and calm. Some believe peridot can promote restful sleep and alleviate anger, even offering relief from depression. It is also the traditional gemstone for celebrating a 15th wedding anniversary.
Sardonyx symbolizes strength and protection. Its reddish-brown color is thought to embody both comfort and power.
Spinel is believed to possess refreshing properties, capable of renewing energy and fostering humility in the face of success. It is associated with perseverance and the acceptance of victory with grace.
Care and Cleaning
Spinel, with its hardness of 8 on the Mohs scale, is relatively durable and can be cleaned using ultrasonic or steam cleaners. However, caution should be exercised if the stone contains fractures. Warm, soapy water is always a safe cleaning option. Spinel is stable when exposed to light and chemicals, but prolonged exposure to high heat may cause some colors to fade.
Peridot and sardonyx, with a Mohs hardness of 6.5-7, require more gentle care. Cleaning should be done with warm, soapy water and a soft cloth. Avoid harsh chemicals and ultrasonic cleaners, as these could damage the stones.
Conclusion
August’s birthstones – peridot, sardonyx, and spinel – offer a captivating array of colors, histories, and symbolic meanings. From the ancient origins of sardonyx and peridot to the recent recognition of spinel as a prominent August gem, these stones represent a rich tapestry of geological processes, cultural beliefs, and enduring beauty. Whether chosen for their aesthetic appeal, historical significance, or perceived metaphysical properties, these three gemstones provide a meaningful connection to the month of August and the individuals born within it.