August is one of the few months to boast three official birthstones: peridot, spinel, and sardonyx. Each of these gemstones offers a unique blend of beauty, history, and symbolism, making them treasured choices for jewelry and personal adornment. This article explores the geological origins, historical significance, gemological properties, and cultural meanings of these three August birthstones, drawing on a wealth of expert and historical sources.
Historical Significance and Lore
Sardonyx: The Original August Birthstone
Sardonyx is the oldest of the three August birthstones, with a documented history stretching back more than 4,000 years. Its name is derived from the Greek words “sard,” meaning “reddish-brown,” and “onyx,” meaning “veined gem,” reflecting its typical appearance as a reddish-brown stone with white or yellow bands. Sardonyx is a type of chalcedony, a cryptocrystalline form of silica, and has long been valued for its durability and ability to take a fine polish.
Historically, sardonyx was used in ancient amulets, cameos, and seals. The Greeks and Romans, in particular, believed that the stone brought courage and protection in battle. Ancient Roman soldiers wore sardonyx amulets as charms for strength and victory, while orators used it as a talisman to enhance their communication skills. Its use in engraved gemstones for seals and cameos also reflects its importance in administrative and artistic contexts.
Sardonyx was the sole official birthstone for August until the 20th century. Its inclusion was largely due to its long-standing association with the month and its practicality for carving. However, as other gemstones like peridot and spinel gained popularity and recognition, sardonyx was joined by these two newer additions in the modern birthstone list.
Peridot: The “Evening Emerald”
Peridot, the yellowish-green gem variety of olivine, has a long and storied history. Known for its vibrant, glassy luster, peridot was once mistaken for emerald or topaz due to its color and clarity. The gem’s name may be linked to the Red Sea island of Topazios, where peridot was mined in ancient times. This island, known in Arabic as Zabargad, was one of the earliest and most important sources of peridot.
Peridot is notable for its unique geological formation. It is formed under extreme conditions and can be found in the hardened lava that carried it from deep within Earth’s mantle. It is also found in meteorites, making it one of the few gemstones that can be traced back to outer space. This cosmic origin has added to its mystique and allure over the centuries.
Historically, peridot was believed to have protective and healing properties. It was often used in jewelry to ward off nightmares and negative energies. The Shrine of the Three Holy Kings in Cologne Cathedral, for example, is adorned with 200 carats of gems that were once thought to be emeralds but are now identified as peridot. Some historians even speculate that Cleopatra’s famed emerald collection may have actually been composed of peridot.
Spinel: The Overlooked Gem
Spinel, the newest of the three August birthstones, was officially recognized in 2016 by the American Gem Trade Association and the Jewelers of America. For centuries, spinel was often mistaken for ruby or sapphire due to its similar color and brilliance. This misidentification led to its underappreciation and limited recognition as a gemstone in its own right.
Spinel is a distinct mineral species with a different chemical composition and crystal structure than ruby or sapphire. While it can appear in a wide range of colors, including red, blue, pink, and black, the most valuable and sought-after spinel stones are those with intense, vivid colors. The gem’s durability and brilliance make it a versatile and beautiful option for jewelry.
The recognition of spinel as an August birthstone reflects a modern and inclusive approach to birthstones. It also highlights the growing appreciation for alternative gemstones that offer beauty and value without the high price tags of traditional gems like ruby or sapphire.
Geological Formation and Sources
Peridot: From Earth’s Mantle to Meteorites
Peridot is a gem-quality variety of the mineral olivine, which is composed of magnesium-iron silicates. The gem’s color ranges from a bright lime green to a deep olive green, depending on the amount of iron present in the crystal. The more iron a peridot contains, the more intense its green color becomes.
Peridot is formed in the Earth’s mantle and brought to the surface through volcanic activity. It can also be found in meteorites, where it forms under the extreme heat and pressure of space. The most famous sources of peridot include the Red Sea island of Zabargad, which has been mined for the gem since ancient times. Other notable sources include the San Carlos Indian Reservation in Arizona, Brazil, China, Kenya, Sri Lanka, and the Mogok district of Myanmar.
Peridot is relatively abundant compared to other gemstones, though high-quality stones with a vivid green color and minimal brown or yellow tinge are rare. The finest peridots are often referred to as “evening emeralds” because they appear greener under artificial light.
Sardonyx: A Veined Gem of Volcanic and Metamorphic Origins
Sardonyx is a type of chalcedony, a cryptocrystalline form of silica. It forms in the Earth’s crust, particularly in regions with volcanic and metamorphic activity. The gem is characterized by its banded patterns, which result from alternating layers of different-colored chalcedony. The typical reddish-brown color is due to the presence of iron, while the white or yellow bands are composed of quartz.
Modern sources of sardonyx include Brazil, Germany, Madagascar, and the United States. These countries produce high-quality stones with distinct veining and rich colors. Sardonyx is relatively durable and is often used for carving cameos, seals, and amulets. It is also a popular choice for engraved gemstones and ornamental objects.
Spinel: A Diverse and Durable Gem
Spinel is a mineral composed of magnesium aluminum silicate. It forms in a variety of geological environments, including igneous and metamorphic rocks. The gem’s color is determined by trace elements such as chromium, iron, and cobalt. Red spinel, for example, gets its color from chromium, while blue spinel is colored by cobalt.
Spinel is found in several parts of the world, including Burma (Myanmar), Sri Lanka, Afghanistan, Vietnam, and Tanzania. The most famous historical spinel stones include the “Black Prince’s Ruby” and the “Timur Ruby,” both of which are actually red spinel. These stones were long mistaken for rubies due to their striking red color and brilliance.
Spinel is known for its durability and is rated at 8 on the Mohs scale of hardness. This makes it suitable for use in a wide range of jewelry, including rings, bracelets, and earrings. Its versatility and affordability have contributed to its growing popularity in the gemstone market.
Gemological Properties
Peridot
- Chemical Formula: (Mg, Fe)₂SiO₄
- Color: Yellow-green to olive green
- Hardness (Mohs): 6.5–7
- Refractive Index: 1.65–1.70
- Specific Gravity: 3.25–4.35
- Crystal System: Orthorhombic
- Luster: Vitreous
- Transparency: Transparent to translucent
- Inclusions: Commonly includes small inclusions, which are often accepted as natural features of the gem
Peridot is known for its bright, glassy luster and its ability to display a vivid green color. Its hardness is moderate, which means it requires careful handling to avoid scratches or chips. The gem is often faceted to enhance its brilliance and color.
Sardonyx
- Chemical Formula: SiO₂ (Silicon Dioxide)
- Color: Reddish-brown with white or yellow bands
- Hardness (Mohs): 6.5–7
- Refractive Index: 1.48–1.53
- Specific Gravity: 2.60–2.64
- Crystal System: Trigonal (as a form of quartz)
- Luster: Waxy to dull
- Transparency: Translucent to opaque
- Inclusions: May contain small inclusions, which are typical for chalcedony
Sardonyx is a durable gemstone that is well suited for carving and engraving. Its banded patterns make it ideal for cameos and intaglios. The gem is typically opaque, with a waxy luster, and is often polished to a high finish.
Spinel
- Chemical Formula: MgAl₂O₄
- Color: Red, blue, pink, black, and other colors
- Hardness (Mohs): 8
- Refractive Index: 1.718–1.834
- Specific Gravity: 3.6–4.0
- Crystal System: Isometric
- Luster: Vitreous
- Transparency: Transparent to translucent
- Inclusions: Can contain inclusions such as color zoning or small crystals
Spinel is a versatile gemstone with a wide range of colors and a high degree of clarity. Its hardness makes it suitable for use in all types of jewelry. The gem is often cut in brilliant or mixed cuts to maximize its brilliance and fire.
Symbolism and Metaphysical Beliefs
Sardonyx
Sardonyx has long been associated with strength, courage, and protection. In ancient times, it was believed to provide protection in battle and to enhance communication skills. Roman soldiers wore sardonyx amulets for strength and victory, while orators used it to improve their eloquence.
The gemstone is also associated with self-confidence and assertiveness. It is believed to help individuals overcome fear and stand up for themselves. In some traditions, sardonyx is used to promote a sense of stability and grounding.
Peridot
Peridot has been linked to positive energy, protection, and abundance. It is believed to bring good fortune and to help individuals overcome negativity and fear. The gemstone is also associated with healing and is believed to have a calming effect on the mind and body.
In some traditions, peridot is considered a stone of transformation. It is believed to help individuals release old patterns and emotions, allowing for personal growth and renewal. The gemstone is also associated with the heart chakra and is believed to promote emotional balance and harmony.
Spinel
Spinel is a relatively new addition to the list of August birthstones, but it has a rich history of symbolism and metaphysical properties. It is associated with vitality, energy, and emotional strength. Red spinel, in particular, is believed to boost confidence and courage, while blue spinel is associated with calmness and clarity.
Spinel is also believed to enhance communication and creativity. It is often used in meditation to help individuals connect with their inner self and to promote a sense of inner peace. In some traditions, spinel is considered a stone of protection and is believed to ward off negative energies.
Care and Maintenance
Proper care and maintenance are essential for preserving the beauty and value of August birthstone jewelry. Here are some general guidelines for caring for peridot, spinel, and sardonyx:
Peridot
- Cleaning: Use a soft cloth and mild soap with warm water. Avoid ultrasonic cleaners, as peridot is relatively soft and can be damaged by vibrations.
- Storage: Store peridot separately from harder gemstones to prevent scratches. Keep it away from direct sunlight, as prolonged exposure can cause fading.
- Handling: Avoid wearing peridot during activities that may cause impact or abrasion, such as sports or heavy manual labor.
Sardonyx
- Cleaning: Sardonyx can be cleaned with a soft cloth and mild soap. It is generally safe to use an ultrasonic cleaner, but it is best to avoid steam cleaning, as it can cause damage.
- Storage: Store sardonyx in a cool, dry place away from direct sunlight. It is best to keep it separate from harder gemstones to prevent scratches.
- Handling: Sardonyx is durable, but it should still be handled with care to avoid chips or fractures.
Spinel
- Cleaning: Spinel can be cleaned with a soft cloth and mild soap. It is safe to use an ultrasonic cleaner, but steam cleaning should be avoided.
- Storage: Store spinel in a cool, dry place away from direct sunlight. It is best to keep it separate from other gemstones to avoid scratches.
- Handling: Spinel is durable and can be worn in a wide range of jewelry. However, it should still be handled with care to avoid damage.
Conclusion
The August birthstones—peridot, spinel, and sardonyx—each offer a unique combination of beauty, history, and symbolism. From the deep green glow of peridot to the vibrant colors of spinel and the banded patterns of sardonyx, these gemstones have captivated people for centuries. Whether used in jewelry, amulets, or cameos, these stones continue to be treasured for their enduring beauty and cultural significance.
Understanding the geological origins, gemological properties, and historical lore of these gemstones enhances their value and appreciation. As birthstones, they not only symbolize the month of August but also serve as a connection to the past, a reflection of personal identity, and a celebration of the natural world’s beauty.