August is a unique month in the world of gemology, distinguished by its three official birthstones: peridot, spinel, and sardonyx. This abundance offers individuals born in August a rare opportunity to select a gem that resonates with their personal style and energy. While many months are associated with a single stone, August’s trio reflects a spectrum of colors, histories, and symbolic meanings. Peridot, with its vibrant lime-green glow, is the most widely recognized, but spinel and sardonyx provide equally compelling narratives. Together, these stones embody the warmth, strength, and clarity of summer, from the fiery brilliance of a sunlit field to the enduring legacy of ancient artifacts.
The modern birthstone list, as established by the American Gem Trade Association (AGTA) and Jewelers of America (JA), has evolved over time to provide more options for consumers. Sardonyx holds the title of the traditional August birthstone, a nod to its ancient use in cameos and seals. Peridot became the official modern birthstone in 1912, celebrated for its distinct and luminous color. Most recently, in 2016, spinel was added as a modern alternative, recognizing its remarkable range of hues and its historical misidentification with other precious gems. This article will delve into the rich history, geological origins, gemological properties, and cultural significance of each of these three August stones, providing a comprehensive guide for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
The tradition of associating specific gemstones with birth months has deep historical roots, tracing back to the ancient Breastplate of Aaron described in the Book of Exodus. This sacred garment, worn by the High Priest of the Israelites, featured twelve gemstones representing the twelve tribes of Israel, which were later linked to the zodiac signs and months of the year. The modern concept of birthstones, however, began to crystallize in the 18th century in Poland, where gem traders started assigning specific stones to each month. Over the centuries, these lists were standardized, most notably in 1912 by the National Association of Jewelers in the United States, which laid the foundation for the contemporary birthstone calendar.
Peridot has a particularly storied and sometimes misunderstood history. Often mistaken for emerald due to its rich green hue, some historians believe that Cleopatra’s famed collection of emeralds may have actually been peridot. The oldest recorded source of peridot is the Egyptian island of Zabargad in the Red Sea, which was mined as early as 1500 B.C. The gem’s name is believed to have two possible origins. Some sources, citing the Geological Institute of America, suggest it derives from the Arabic word "faridat," meaning "gem." Others, referencing the American Gem Society, propose a Greek origin from the word "peridona," meaning "giving plenty." This latter meaning aligns perfectly with the gemstone’s long-standing association with prosperity, good fortune, and happiness. In ancient times, peridot was believed to protect against nightmares and bring the wearer strength.
Spinel’s history is one of rediscovery and correction. For centuries, this gem was frequently confused with other precious stones, most notably ruby. Many of the world’s most famous historic "rubies," such as the Black Prince’s Ruby in the British Imperial State Crown, have been identified as red spinel. This long-standing misidentification, while diminishing its historical prestige, underscores spinel’s exceptional beauty. The gem comes in a wide variety of colors, including vivid red, pink, orange, purple, blue, and green, which contributed to its confusion with gems like sapphire and ruby. Only in recent centuries, with advances in gemological science, has spinel been recognized as a distinct mineral with its own unique properties and value.
Sardonyx, the traditional August birthstone, boasts one of the oldest and most continuous histories of use. As a form of onyx composed of parallel layers of sard and carnelian, it has been prized since antiquity for its durability and distinctive banding. Its most famous application was in the creation of cameos and intaglios, where its layered structure was expertly carved to produce intricate designs. Sardonyx was widely used for signet rings and seals, as the carved image would leave a clear impression in wax or clay. This practice was common in ancient Rome and Greece, and sardonyx artifacts from these periods are now displayed in museums worldwide. Its use in the Breastplate of Aaron further solidified its importance in early religious and cultural contexts.
Geological Formation and Sources
Each of the August birthstones forms under different geological conditions and is sourced from distinct regions across the globe. Understanding their origins provides insight into their unique characteristics and rarity.
Peridot is a gem variety of the mineral olivine, which is a common mineral in the Earth’s mantle. Unlike many gemstones that form in igneous or metamorphic rock, peridot is unique in that it is found in two primary geological settings: in igneous rock and in meteorites. The most significant commercial deposits are located in igneous rock, particularly in ultramafic rock and basalts. The gemstone is formed deep within the Earth’s mantle and is brought to the surface through volcanic activity. The oldest and most historically significant source is the Egyptian island of Zabargad. Modern mining sites, as noted in the sources, include China, Myanmar, Pakistan, Tanzania, Vietnam, and the United States. Peridot is also famously found in the lava fields of Hawaii and the mines of Kashmir, known for producing stones with a golden shimmer.
Spinel forms under a variety of geological conditions, primarily in metamorphic rocks and alluvial deposits. It crystallizes in magnesium-rich environments, often in contact with limestone, which is a common setting for gem formation. Major sources of spinel are located in Southeast Asia, particularly in Myanmar (Burma), which is renowned for producing some of the finest red and pink spinels. Other significant sources include Sri Lanka, Thailand, and Vietnam. The gem is also found in East Africa, with Tanzania and Madagascar being notable producers. Spinel is frequently recovered from alluvial deposits, where it has been weathered from its original host rock and transported by water over time.
Sardonyx is a variety of chalcedony, which is a microcrystalline form of quartz. It is composed of alternating layers of sard (a brownish-red variety of chalcedony) and onyx (a black variety of chalcedony). This banding is formed through the deposition of silica-rich fluids in rock cavities, with variations in chemical impurities creating the distinct colored layers. Sardonyx is found in many parts of the world, including India, Brazil, Germany, and the United States. Unlike peridot and spinel, which are mined from hard rock, sardonyx is often collected from sedimentary deposits and alluvial settings. Its formation process is relatively slow, allowing for the development of the characteristic parallel bands that make it so prized for carving.
Gemological Properties
The physical and chemical properties of a gemstone determine its durability, appearance, and care requirements. The three August birthstones possess distinct characteristics that influence their suitability for different types of jewelry.
| Gemstone | Mineral Group | Mohs Hardness | Chemical Formula | Typical Colors | Cleavage/Fracture |
|---|---|---|---|---|---|
| Peridot | Olivine | 6.5 – 7 | (Mg,Fe)₂SiO₄ | Lime green, olive green, yellow-green | Conchoidal to uneven fracture; poor cleavage |
| Spinel | Spinel | 8 | MgAl₂O₄ | Red, pink, orange, purple, blue, green | Conchoidal fracture; no cleavage |
| Sardonyx | Chalcedony (Quartz) | 7 | SiO₂ | Bands of brownish-red (sard) and black (onyx) | Conchoidal fracture; no cleavage |
Peridot is a member of the olivine group, with a chemical formula of (Mg,Fe)₂SiO₄. Its color ranges from a bright, zesty lime green (as seen in Arizona peridot) to a deeper, earthy olive green (characteristic of Burmese peridot) and a warmer, golden yellow-green (typical of Pakistani peridot). The iron content within its structure is responsible for its green hue. With a Mohs hardness of 6.5 to 7, peridot is moderately durable, suitable for earrings, pendants, and occasional-wear rings, though it can be susceptible to scratching and chipping with rough use. It has poor cleavage, meaning it does not break easily along flat planes, but its conchoidal fracture can make it vulnerable to impact. Peridot is not treated in any significant way; its color is natural.
Spinel is a magnesium aluminate spinel with the formula MgAl₂O₄. It is prized for its exceptional hardness of 8 on the Mohs scale, making it one of the most durable gemstones, highly resistant to scratching and ideal for all types of jewelry, including daily-wear rings. Spinel exhibits a brilliant, glassy luster and comes in an astonishing array of colors. While red spinel is the most famous and valuable, the gem also occurs naturally in vibrant pinks, rich oranges, deep purples, brilliant blues, and even greens. It has no cleavage and fractures in a conchoidal manner, contributing to its toughness. Like peridot, spinel is typically untreated, and its colors are entirely natural.
Sardonyx is a variety of chalcedony, which is composed of silicon dioxide (SiO₂). As a member of the quartz family, it has a Mohs hardness of 7, making it reasonably durable for various jewelry applications. Its defining feature is the sharp, parallel banding of contrasting colors—typically layers of sard (brownish-red) and onyx (black). This banded structure is a result of its formation process. Sardonyx is often cut in a cabochon (a smooth, rounded shape) to showcase its bands, especially for cameos and intaglios. It is sometimes dyed or heat-treated to enhance the color contrast between the layers, but natural sardonyx is valued for its organic banding. Its toughness is good, with no cleavage, making it suitable for carving and intricate jewelry work.
Symbolism and Metaphysical Beliefs
Beyond their physical beauty, the August birthstones are rich in symbolism and metaphysical beliefs, which have been attributed to them across different cultures and eras.
Peridot is overwhelmingly associated with the sun. Its bright green color is said to capture the essence of sunlight, and historically, it was believed to be a stone of light and positivity. The ancient Egyptians called it the "gem of the sun," believing it protected against the darkness of night and brought happiness and strength to the wearer. In line with its name meaning "giving plenty," peridot is widely regarded as a stone of prosperity and good fortune. It is also linked to clarity of mind, believed to help alleviate stress, jealousy, and anger, and to promote emotional balance. In Indian astrology, peridot is sometimes worn for benefits associated with the planet Mercury.
Spinel is often associated with revitalization and renewal. Its vibrant colors, especially the red and pink varieties, are thought to inspire passion, love, and compassion. Some traditions link spinel to the root chakra, believing it provides grounding energy and enhances physical vitality. Due to its long history of being mistaken for ruby, spinel has also inherited some of the symbolic meanings of that stone, including royalty, power, and protection. Its durability is sometimes metaphorically linked to resilience and perseverance, making it a stone for overcoming challenges.
Sardonyx, with its ancient use in seals and amulets, is traditionally a stone of protection and strength. It was believed to guard against negative energies and evil spirits, and to bring stability and courage to the wearer. The banding of sardonyx, with its layers of strength and protection, is said to symbolize harmony and balance. In some traditions, sardonyx is associated with longevity and good health. Its historical use in cameos and intaglios, which often depicted gods, heroes, and scenes of virtue, further ties it to concepts of nobility, integrity, and moral strength.
The zodiac signs of Leo (July 23 – August 22) and Virgo (August 23 – September 22) are also connected to August birthstones. Peridot, with its vibrant and confident energy, is often linked to the fiery and charismatic Leo sign. Spinel and sardonyx, with their grounding and balanced traits, are associated with the practical and organized Virgo sign. This alignment allows individuals to choose a stone that not only matches their birth month but also complements their astrological characteristics.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of any gemstone jewelry. The durability of each August birthstone dictates specific cleaning and handling guidelines.
Peridot, with its hardness of 6.5 to 7, requires careful handling to avoid scratches and chips. It should be cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaners, as the heat and vibrations can cause damage, especially if the stone has any inclusions or fractures. Peridot should be stored separately from harder gemstones like diamonds and sapphires to prevent scratching. It is also advisable to remove peridot jewelry before engaging in physical activities or household chores.
Spinel, ranking 8 on the Mohs scale, is exceptionally durable and can be cleaned with relative ease. It is safe to use warm, soapy water and a soft brush. Spinel is generally resistant to chemicals and heat, making it suitable for ultrasonic cleaners, though it is always best to check with a professional jeweler first, especially if the spinel is set in a delicate mounting. Its toughness makes it an excellent choice for rings and bracelets that are worn daily.
Sardonyx, with a hardness of 7, is also quite durable. It can be cleaned with warm, soapy water and a soft cloth or brush. Like peridot, it should be protected from harsh chemicals and sudden temperature changes, which could potentially damage the stone or its setting. For sardonyx used in cameos or carved pieces, extra care should be taken to clean the crevices and details without using abrasive materials that could wear down the carving. Ultrasonic cleaners are generally safe for sardonyx, but caution is advised for pieces with glued components.
For all three gemstones, it is recommended to have jewelry inspected periodically by a professional jeweler to ensure the settings are secure and the stones are in good condition. Storing each piece separately in a soft-lined jewelry box will help prevent scratches and tangling.
Conclusion
The three birthstones of August—peridot, spinel, and sardonyx—offer a remarkable diversity of color, history, and meaning. From the sun-kissed green of peridot, a gem of prosperity and ancient Egyptian lore, to the fiery resilience of spinel, a stone long mistaken for ruby, and the ancient, protective banding of sardonyx, each gem provides a unique connection to the past and a distinct aesthetic for the present. Their geological origins span volcanic landscapes, metamorphic environments, and sedimentary deposits, reflecting the varied processes of the Earth itself. With their specific gemological properties—from peridot’s moderate hardness to spinel’s exceptional durability and sardonyx’s distinctive banding—they each require mindful care to preserve their beauty. Ultimately, the abundance of choice in August allows for a deeply personal selection, enabling those born in this summer month to wear a gemstone that not only marks their birth but also resonates with their individual style, beliefs, and energy.