August, the eighth month of the year, is a month of late summer warmth and vibrant life. Historically, it was named after Augustus Caesar, the first Roman emperor, and originally bore the name Sextilis. For those born in this month, the tradition of birthstones offers a rich tapestry of choice: peridot, spinel, and sardonyx. These three gemstones, each with distinct properties, origins, and symbolic meanings, collectively represent the August birthstones. While peridot is the most widely recognized of the trio, the inclusion of spinel in 2016 and the enduring presence of sardonyx underscore the evolving nature of birthstone traditions. This article explores the geological, historical, and cultural significance of these August birthstones, drawing from authoritative and widely corroborated sources to present an in-depth examination of their role in gemology and beyond.
History and Lore
The practice of associating gemstones with specific months dates back thousands of years, with roots in ancient civilizations that believed in the protective and healing properties of stones. The earliest known record of birthstones is found in the Breastplate of Aaron, described in the Old Testament, where 12 gemstones were set into a priestly garment to represent the 12 tribes of Israel. Though the identities of these stones are debated, the concept of linking gemstones to months and individuals became widespread in the medieval and Renaissance periods.
In the case of August, the selection of birthstones has evolved significantly over time. Sardonyx, a banded chalcedony with a reddish-brown base and white bands, has been recognized as an August birthstone for over 4,000 years. Its historical significance is reflected in its use in ancient Roman and Egyptian jewelry, where it was believed to promote fidelity and protect against negative energies. Sardonyx was also associated with the Roman poet Virgil, who reportedly wore the stone for inspiration.
Peridot, the modern August birthstone, has a rich and varied history. Known in antiquity as chrysolite, peridot was often confused with other green gemstones such as topaz and emerald. The Red Sea island of Topazios, now known as St. John's Island in Egypt, was a primary source of peridot in ancient times. Interestingly, the name "topaz" is thought to have originated from this island, even though the gemstone found there was not actually topaz. Peridot was also mistakenly believed to be emerald in some historical contexts—most notably in the Shrine of the Three Holy Kings in Cologne Cathedral, which contains over 200 carats of what were once thought to be emeralds but are now identified as peridot.
In addition to peridot and sardonyx, several other stones have been historically linked to August. These include carnelian, a red-orange chalcedony associated with passion and vitality; alexandrite, a rare color-changing gemstone from Russia; and ruby, the August birthstone in the Hindu calendar. More recently, spinel has been added to the official August birthstone list in recognition of its beauty and growing popularity as a gemstone alternative to ruby and other red stones.
The modern standardization of birthstones occurred in 1912 when the American National Retail Jewelers Association (now Jewelers of America) issued a formal list. Peridot was designated as the sole August birthstone at that time. In 2016, spinel was added to the list to offer consumers more choices and to reflect contemporary gemological trends.
Geological Formation and Sources
Each of the three August birthstones—peridot, spinel, and sardonyx—has a distinct geological origin, formed under different conditions and found in specific locations around the world.
Peridot
Peridot is a gem variety of the mineral olivine, a magnesium iron silicate with the chemical formula (Mg,Fe)₂SiO₄. It forms in the Earth's upper mantle under high-pressure and high-temperature conditions and is brought to the surface through volcanic activity or meteorite impacts. Peridot can also be found in meteorites, making it one of the few gemstones that originate from outer space. The most notable sources of peridot include:
- Zambia: Known for producing high-quality peridot, Zambia is the largest producer of the gemstone.
- United States: Arizona is a significant source, particularly for peridot found in volcanic rocks.
- Egypt: The Red Sea island of St. John’s was a historical source and is still known for its peridot deposits.
- Nigeria, Brazil, and China: These countries also have notable peridot occurrences.
Peridot is typically found in a range of green tones, from yellowish green to deep olive. It has a hardness of 6.5 to 7 on the Mohs scale, making it relatively durable but still requiring care to avoid scratches and fractures.
Spinel
Spinel is an oxide mineral with the chemical formula MgAl₂O₄. It forms in metamorphic and igneous rocks and is often found in association with corundum (ruby and sapphire). Spinel is known for its wide range of colors, including red, pink, blue, violet, and black. Red spinel, in particular, has often been mistaken for ruby due to its similar appearance. The primary sources of spinel include:
- Afghanistan: A historic source of fine red and pink spinel.
- Sri Lanka: Known for producing high-quality spinel in various colors.
- Myanmar (Burma): A significant source, particularly for red and pink spinel.
- Vietnam and Tanzania: Also notable for their spinel deposits.
Spinel has a hardness of 8 on the Mohs scale, making it one of the more durable gemstones. Its refractive index ranges from 1.718 to 1.736, giving it a brilliant luster when cut and polished.
Sardonyx
Sardonyx is a type of chalcedony, a microcrystalline quartz, characterized by alternating bands of sard (a reddish-brown chalcedony) and onyx (a white or black chalcedony). It is formed through the slow deposition of silica in sedimentary rock, often in geodes or veins. Sardonyx is known for its durability and is commonly used for carvings, seals, and intaglios. Key sources include:
- Brazil: The largest and most consistent producer of sardonyx.
- India: A significant historical and modern source, particularly for high-quality material.
- Madagascar and Uruguay: Also known for producing fine sardonyx.
Sardonyx has a hardness of 6.5 to 7 on the Mohs scale and a refractive index of 1.486 to 1.530. Its banded appearance is highly valued in jewelry, especially in rings and pendants.
Gemological Properties
Each of the August birthstones has unique gemological characteristics that influence their appearance, durability, and use in jewelry.
Peridot
- Color: Peridot is most commonly found in shades of green, ranging from yellowish green to deep olive. The color is due to the presence of iron in the crystal structure.
- Hardness: 6.5 to 7 on the Mohs scale. This makes it relatively durable but still susceptible to scratches and fractures.
- Luster: Vitreous (glassy).
- Refractive Index: 1.654 to 1.690.
- Cleavage: Peridot has perfect cleavage in two directions at 87° and 93°, making it relatively fragile when struck along the cleavage planes.
- Cut: Peridot is commonly cut into round, oval, and emerald cuts to enhance its brilliance and color.
Spinel
- Color: Spinel occurs in a wide range of colors, including red, pink, blue, violet, and black. Red spinel is particularly notable for its similarity to ruby.
- Hardness: 8 on the Mohs scale, making it one of the more durable gemstones.
- Luster: Vitreous.
- Refractive Index: 1.718 to 1.736.
- Cleavage: Spinel has no cleavage, which makes it more durable than peridot.
- Cut: Spinel is often cut into round, oval, cushion, and princess cuts to highlight its brilliance and color.
Sardonyx
- Color: Sardonyx is characterized by alternating bands of sard (reddish-brown) and onyx (white or black).
- Hardness: 6.5 to 7 on the Mohs scale.
- Luster: Waxy to vitreous, depending on the cut and polish.
- Refractive Index: 1.486 to 1.530.
- Cleavage: Sardonyx has no cleavage, making it relatively durable.
- Cut: Sardonyx is often cut into cabochons for carvings and intaglios, as well as faceted cuts for jewelry.
Symbolism and Metaphysical Beliefs
The August birthstones have long been associated with various symbolic meanings and metaphysical properties, reflecting the cultural and spiritual beliefs of different civilizations.
Peridot
Peridot has been revered for its protective and calming properties. In ancient Egypt, it was believed to be a gift from the sun god Ra and was used in jewelry and amulets to ward off nightmares and negative energies. In medieval Europe, peridot was thought to bring good fortune and was often used in wedding rings to promote fidelity. Modern metaphysical beliefs suggest that peridot can reduce stress, enhance self-confidence, and promote emotional healing.
Spinel
Spinel has been associated with vitality and passion. In ancient times, it was believed to have protective properties and was used in talismans to ward off evil spirits. Red spinel, in particular, is thought to boost courage, energy, and motivation. Some cultures also associate spinel with love and romance, making it a popular choice for engagement rings and love charms.
Sardonyx
Sardonyx has a long history of being linked to protection, strength, and success. In ancient Rome, it was considered a stone of power and was often worn by soldiers and leaders for courage and victory. Sardonyx was also believed to promote fidelity and was used in wedding rings and other romantic jewelry. In medieval Europe, it was associated with chastity and was used in seals and rings to symbolize loyalty and commitment.
Care and Cleaning
Proper care and cleaning are essential for maintaining the beauty and longevity of August birthstones. Each stone has specific care requirements based on its hardness, cleavage, and sensitivity to heat and chemicals.
Peridot
- Cleaning: Peridot should be cleaned using warm, soapy water and a soft brush. Avoid using ultrasonic or steam cleaners, as these can damage the stone, especially if it has inclusions or is set in a delicate setting.
- Storage: Store peridot separately from harder gemstones to prevent scratches. A soft cloth or padded box is ideal.
- Avoid: Exposure to harsh chemicals, extreme temperatures, and impacts along the cleavage planes.
Spinel
- Cleaning: Spinel can be cleaned using warm, soapy water and a soft brush. It is also safe to use ultrasonic and steam cleaners, provided the stone is free of inclusions and is not set in a delicate setting.
- Storage: Store spinel separately from harder gemstones to prevent scratches.
- Avoid: Exposure to harsh chemicals and extreme temperatures, though it is generally more durable than peridot.
Sardonyx
- Cleaning: Sardonyx can be cleaned using warm, soapy water and a soft brush. Avoid using ultrasonic or steam cleaners, as these can cause damage to the banded structure of the stone.
- Storage: Store sardonyx separately from harder gemstones to prevent scratches.
- Avoid: Exposure to harsh chemicals and abrasive materials.
Conclusion
The August birthstones—peridot, spinel, and sardonyx—each offer a unique combination of beauty, history, and symbolism. Peridot, with its vibrant green color and ancient origins, has long been associated with protection and emotional healing. Spinel, a gemstone of resilience and brilliance, has gained popularity as a modern alternative to ruby and other red gems. Sardonyx, with its banded appearance and enduring appeal, has been a symbol of strength and fidelity for thousands of years. Together, these gemstones represent the rich tradition of birthstones and continue to be cherished for their beauty and meaning. Whether chosen for their historical significance, gemological properties, or metaphysical beliefs, August birthstones remain a testament to the enduring fascination with gemstones and their role in human culture.