The tradition of associating specific gemstones with each month of the year has a rich and complex history, stretching back to biblical times and evolving through various cultural interpretations. While the modern list of birthstones solidified in 1912, with tanzanite being the most recent addition, the practice itself is ancient, originating with the twelve gemstones adorning the breastplate of Aaron, representing the twelve tribes of Israel. August, notably, boasts three recognized birthstones: peridot, spinel, and sardonyx, each with its own unique history, geological origins, and symbolic significance. This article will explore these three gemstones, drawing upon available information to provide a comprehensive overview of their properties and cultural relevance.
History and Lore
The origins of birthstone associations are deeply rooted in ancient beliefs regarding the healing powers and symbolic meanings of gemstones. The practice of assigning a gem to each month likely evolved from astrological correlations and the perceived influence of gemstones on health and fortune. While the specific attributions have shifted over time, the underlying concept of a personal gemstone linked to one’s birth month has endured.
Sardonyx holds the distinction of being the most ancient of the August birthstones, with evidence of its use dating back to ancient Rome. Romans favored sardonyx for creating seals and signet rings, appreciating its unique property of resisting hot wax – a crucial feature for authentication purposes. The banding of colors within sardonyx also made it a popular material for carving cameos and intaglios, intricate relief carvings that were highly valued artistic expressions.
Peridot’s history is also extensive, with finds dating back to ancient Egypt. It was often associated with the sun and believed to ward off evil spirits. More recently, discoveries in Tanzania in 2007 brought a new vibrancy to the spinel market, captivating gem collectors with its pinkish and orangy-red hues, alongside the more traditional purple and blue varieties.
Geological Formation and Sources
The formation of these three August birthstones occurs through distinct geological processes and in geographically diverse locations.
Peridot, a gem variety of the mineral olivine, is often found in unusual circumstances. While it can form in igneous rocks, some of the most remarkable peridot crystals originate from pallasite meteorites – a rare type of stony-iron meteorite. Thousands of meteorites have impacted Earth, and some contain gem-quality peridot. However, terrestrial sources are also significant. Myanmar (Burma) is known for producing high-quality peridot with deep color and transparency, found on the northern slope of Kyaukpon. Arizona, in the United States, is another important source, with volcanic eruptions creating deposits on the San Carlos Apache Indian Reservation, where some Apache families have mined the gem for decades.
Spinel forms in metamorphic rocks and alluvial deposits. Tanzania has emerged as a significant source, producing spinel in a range of colors, including pink, orange, purple, and blue. Historically, Myanmar was also a key source of spinel.
Sardonyx, being a variety of chalcedony, forms through the layering of silica-rich fluids within volcanic rocks. It is created from bands of brownish-red to brown to dark orange sard alternating with typically white or black layers of onyx.
Gemological Properties
Each of the August birthstones possesses unique gemological properties that contribute to its distinct appearance and durability.
Peridot: With a hardness of 6.5 to 7 on the Mohs scale, peridot is relatively soft compared to many other gemstones. This makes it less suitable for daily wear in rings, as it is susceptible to scratching. It requires careful cleaning, avoiding ultrasonic or steam cleaners due to its vulnerability to thermal shock. Warm soapy water and a soft brush are the safest cleaning methods.
Spinel: Spinel boasts a hardness of 8 on the Mohs scale, making it a durable gem suitable for all types of jewelry, including rings. It is generally stable when exposed to light and chemicals, though high heat can cause some colors to fade. Ultrasonic and steam cleaners can be used, but caution is advised if the stone contains fractures.
Sardonyx: As a form of chalcedony, sardonyx is composed of cryptocrystalline quartz. Its hardness is not explicitly stated in the provided sources. Its defining characteristic is the banded appearance of sard and onyx layers.
The following table summarizes the key properties:
| Gemstone | Hardness (Mohs) | Primary Composition | Notable Characteristics |
|---|---|---|---|
| Peridot | 6.5 - 7 | Olivine | Vulnerable to thermal shock, requires gentle cleaning |
| Spinel | 8 | Magnesium Aluminum Oxide | Durable, stable to light and chemicals |
| Sardonyx | N/A | Cryptocrystalline Quartz | Banded layers of sard and onyx |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meanings and believed to possess various powers.
While the sources do not detail extensive metaphysical beliefs surrounding peridot and spinel, sardonyx was historically used by the Babylonians to create amulets and seals believed to promote healing, particularly for blood disorders. A legend associates the stone with a drop of Christ’s blood falling onto jasper during the crucifixion.
The sources mention that garnets signify everlasting friendship and trust, amethysts represent royalty and were believed to ward off the powers of Bacchus, and emeralds symbolize rebirth and were thought to grant foresight, good fortune, and youthfulness. These examples demonstrate the broader historical trend of attributing specific powers and meanings to gemstones.
Care and Cleaning
Proper care and cleaning are essential to maintain the beauty and longevity of these August birthstones. As noted previously, peridot requires the most delicate handling due to its lower hardness and susceptibility to thermal shock. Spinel, being more durable, can withstand more rigorous cleaning methods. Sardonyx, as a form of quartz, is relatively resilient but should still be handled with care to avoid scratching or damage to its banded structure.
Conclusion
The August birthstones – peridot, spinel, and sardonyx – represent a fascinating intersection of geological processes, historical lore, and cultural significance. From the ancient Roman use of sardonyx for seals to the recent discoveries of vibrant spinel in Tanzania and the celestial origins of peridot in meteorites, each gemstone possesses a unique story. Understanding their properties and histories allows for a deeper appreciation of these beautiful and enduring symbols of August.