The month of August is uniquely distinguished in the world of birthstones, offering a diverse palette of colors and a rich history that spans millennia. Unlike months with a single gem, August is associated with three official modern birthstones: peridot, spinel, and sardonyx. This trio represents a fascinating evolution from ancient tradition to modern preference. The original August birthstone, sardonyx, boasts a history dating back over 4,000 years and is deeply rooted in biblical lore. Peridot, the vibrant yellowish-green gem, has a history often entangled with topaz and emerald, having been mistaken for these more famous stones throughout antiquity. Most recently, spinel, a brilliant gem available in a spectrum of colors but most famous for its deep red varieties, was added to the official list in 2016, offering a modern and durable alternative to ruby.
This article will explore the distinct characteristics of these three gems. We will delve into the historical journey of each stone, from their geological origins deep within the Earth and in outer space to their roles in ancient cultures and religious artifacts. We will examine their key gemological properties, including hardness, chemical composition, and color variations, providing a scientific basis for understanding their value and durability. Furthermore, we will discuss the symbolism and metaphysical beliefs that have been attributed to these stones across different eras and cultures, and offer practical advice on their care and cleaning to ensure their lasting beauty.
The Original August Birthstone: Sardonyx
Sardonyx holds the distinction of being the original and most historically significant birthstone for August. Its use as a gemstone and carving material dates back more than 4,000 years, making it one of the earliest known decorative stones utilized by ancient civilizations. This banded variety of onyx, composed of layers of sard and onyx, creates a striking contrast of reddish-brown and white or black bands, which have been prized by artisans for centuries.
History and Lore
The historical importance of sardonyx is deeply intertwined with ancient religious and cultural practices. It is explicitly referenced in the Bible as one of the gems featured in the high priest’s breastplate, a precursor to the modern concept of birthstones. Furthermore, sardonyx is identified as one of the twelve foundation stones of Jerusalem’s walls in biblical tradition, cementing its sacred status. The stone’s appeal extended beyond religious contexts; it was a favored material for cameos and intaglios in ancient Rome and Greece, where its distinct banding was expertly utilized to create detailed, multi-toned reliefs and seals.
Geological Formation and Sources
Sardonyx is a variety of chalcedony, which is a microcrystalline form of quartz (silicon dioxide, SiO₂). Its unique banding is the result of successive layers of sard (a reddish-brown chalcedony) and onyx (a white or black chalcedony) being deposited. This process occurs in volcanic or igneous rock environments where silica-rich solutions fill cavities and layer over time. While specific modern mining locations are not detailed in the provided materials, its historical prevalence suggests it was sourced from regions accessible to ancient civilizations in the Middle East and Europe.
Gemological Properties
As a member of the quartz family, sardonyx has distinct physical characteristics that influence its use and care.
- Hardness: It ranks a 6.5 to 7 on the Mohs scale of mineral hardness. This makes it reasonably durable for jewelry, though it can be scratched by harder materials.
- Composition: Its chemical formula is silicon dioxide (SiO₂).
- Appearance: Sardonyx is characterized by its alternating layers of reddish-brown sard and white or black onyx, creating a banded, opaque appearance.
- Cut: It is most commonly cut en cabochon (a smooth, polished dome) to best display its banding, and is also the premier material for cameos and intaglios.
Care and Cleaning
Due to its hardness of 6.5 to 7 on the Mohs scale, sardonyx is relatively durable but can still be scratched by harder gems like diamonds, sapphires, and rubies. It is also important to note that while quartz has a good hardness, it can be subject to cleavage, meaning it can be fractured by a sharp blow. Therefore, sardonyx jewelry should be stored separately to avoid contact with other stones. Cleaning is straightforward: use warm, soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes, which could potentially damage the stone.
The Vibrant Green: Peridot
Peridot, with its distinctive olive to yellowish-green hue, is the second of August’s traditional birthstones. Its formation under extreme conditions makes it a geological marvel, and its history is filled with cases of mistaken identity, where it was often mistaken for more famous green gems like emerald and topaz.
History and Lore
Peridot has a long and often confused history. Many scholars believe that the "topaz" mentioned in historical and biblical texts was, in fact, peridot. This confusion is rooted in the history of Topazios (now Zabargad), a Red Sea island that was a primary source of peridot but whose name was associated with topaz. The gem’s identity was further obscured when it was mistaken for emerald. The 200-carats of gems adorning the Shrine of the Three Holy Kings in Germany’s Cologne Cathedral, long believed to be emeralds, were later identified as peridot. Some historians even speculate that Cleopatra’s famous emerald collection may have been composed of large peridot stones. The name "peridot" itself is derived from the Arabic word faridat, meaning "gem."
Geological Formation and Sources
Peridot is the gem variety of the mineral olivine, with a chemical formula of (Mg,Fe)₂SiO₄. Its formation is unique and occurs under extreme geological conditions. It can be found in hardened lava brought up from deep within the Earth’s mantle, and remarkably, it is also found in meteorites that have traveled from outer space, making it one of the few gems not formed in the Earth’s crust. Historically, the primary source was the Red Sea island of Topazios (Zabargad), which produced peridot for thousands of years.
Gemological Properties
Peridot is prized for its consistently beautiful color and good durability.
- Hardness: It ranks 6.5 to 7 on the Mohs scale, the same as sardonyx.
- Composition: It is the magnesium-iron silicate, olivine.
- Color: Its signature color ranges from yellowish-green to greenish yellow, with the most valued color being a rich olive green.
- Clarity: Peridot is typically free of visible inclusions, giving it a clean and brilliant appearance.
Symbolism and Metaphysical Beliefs
According to some sources, peridot is associated with positivity, growth, and resilience. It is said to be connected to the Heart Chakra and is believed to offer physical benefits related to the lungs, sinuses, and heart.
Care and Cleaning
Like sardonyx, peridot’s hardness of 6.5 to 7 makes it suitable for most jewelry, but it requires care to prevent scratching. It is more susceptible to damage from sharp blows due to its chemical composition and crystal structure. Cleaning should be done with warm, soapy water and a soft brush. It is advisable to avoid extreme temperature changes and harsh chemicals, which could harm the stone.
The Modern Addition: Spinel
Spinel is the newest official birthstone for August, having been added to the modern list in 2016 by the Jewelers of America (JA) and the American Gem Trade Association (AGTA). For centuries, spinel was underappreciated, often serving as an unwitting substitute for ruby. Its recent recognition celebrates its own inherent beauty, durability, and wide range of available colors.
History and Lore
Spinel’s history is one of mistaken identity. For centuries, the most prized red spinels were misidentified as rubies. Many famous "rubies" in royal collections, such as the Black Prince's Ruby in the British Imperial State Crown, are in fact large red spinels. This historical confusion is why spinel was underappreciated for so long. Its addition to the birthstone list in 2016 was an unprecedented update, reflecting a modern shift in consumer preferences towards alternative gems and acknowledging spinel’s own merits.
Geological Formation and Sources
Spinel is a magnesium aluminium oxide (MgAl₂O₄), forming in the metamorphic rock environments of marble, as well as in alluvial deposits. It crystallizes under high temperatures and pressures, often in association with corundum (ruby and sapphire). While specific mining locations are not provided in the sources, spinel is found in various locations around the world, including Myanmar, Sri Lanka, and Tanzania.
Gemological Properties
Spinel is valued for its exceptional brilliance and durability, making it an excellent gemstone for jewelry.
- Hardness: It ranks an 8 on the Mohs scale, making it significantly harder and more scratch-resistant than both peridot and sardonyx.
- Composition: Its chemical formula is magnesium aluminium oxide (MgAl₂O₄).
- Color: Spinel is available in a dazzling array of colors, from vibrant reds and pinks to blues, purples, and blacks. The red varieties are the most famous and were historically mistaken for ruby.
- Brilliance: It has a high refractive index, giving it a brilliant luster and sparkle that rivals many other popular gems.
Symbolism and Metaphysical Beliefs
Spinel is seen as a stone of strength, vitality, and creative inspiration. Its dazzling brilliance and durability are thought to symbolize resilience and energy.
Care and Cleaning
With a hardness of 8 on the Mohs scale, spinel is quite durable and suitable for all types of jewelry, including rings and bracelets that are subject to daily wear. It is less prone to scratching than peridot or sardonyx. Cleaning is simple and safe: warm, soapy water and a soft brush are all that is needed. It is generally stable when exposed to light and heat.
Conclusion
The birthstones of August—sardonyx, peridot, and spinel—offer a remarkable journey through geological time, human history, and gemological science. Sardonyx represents the ancient world, with its banded layers telling a story of millennia of human use and its deep ties to religious tradition. Peridot, the gem of the mantle and meteorites, captivates with its unique olive-green hue and a history rich with cases of mistaken identity, linking it to the treasures of Cleopatra and the altars of medieval cathedrals. Spinel, the modern newcomer, steps out from the shadow of the ruby to claim its place as a durable, brilliant, and versatile gem in its own right. Together, they provide those born in August with a rich selection of gems, each possessing a unique beauty, a storied past, and a distinct place in the world of gemstones.