August, the eighth month of the year, is distinguished by its vibrant trio of birthstones: peridot, spinel, and sardonyx. Each of these gemstones carries a unique history, a set of distinct gemological properties, and a rich tapestry of cultural and symbolic significance. This article delves into the origins, properties, and meanings of these three August birthstones, offering a comprehensive overview for gemstone enthusiasts, jewelry buyers, and students of gemology.
Introduction
August is the only month that boasts three official birthstones: peridot, spinel, and sardonyx. This unique distinction reflects the diverse and rich geological and historical contexts that each stone represents. Peridot, the most well-known of the trio, is a vivid green gemstone that has been revered for millennia. Spinel, once mistaken for ruby, has only recently gained recognition as an official birthstone. Sardonyx, the oldest of the three, is a banded chalcedony with a history stretching back thousands of years. Together, these stones offer a compelling narrative of Earth’s geological processes, human history, and cultural beliefs.
This article explores the geological formation and properties of each gemstone, their historical and cultural significance, and practical advice on how to care for them. The information presented is drawn exclusively from authoritative and reliable sources, ensuring the accuracy and integrity of the content.
History and Lore
Peridot: The “Evening Emerald”
Peridot has a long and storied history, with evidence of its use dating back to ancient Egypt around 1500 BC. It was known as the “gem of the sun” and was believed to protect against nightmares, bringing confidence, health, and positive energy. The ancient Egyptians sourced their peridot from the volcanic island of Zabargad in the Red Sea, a location that remained a significant source of the gemstone until the early 20th century.
Peridot was also valued in Europe during the Middle Ages. It was often used to decorate church altars and clerical robes. During the Victorian era, peridot was frequently used in jewelry, reflecting its enduring appeal and versatility.
In modern times, peridot has been discovered in hardened lava flows and meteorites, giving it a cosmic origin that adds to its allure. It is often referred to as the “evening emerald” due to its brilliant green hue that appears to shine even in low light.
Spinels: The Misunderstood Gemstone
Spinels have long been misunderstood and often mistaken for rubies and other red gemstones. This misidentification persisted for centuries, even among experts. However, spinel has recently gained recognition as a distinct and valuable gemstone. In 2016, it was officially designated as one of the August birthstones.
Spinels come in a wide range of colors, including intense red, vivid pink, orange, purple, violet, blue, and bluish green. This diversity in color makes spinel a unique and versatile gemstone. Spinels are also known for their durability and brilliance, making them a popular choice for jewelry.
Historically, spinel was a traditional wedding anniversary gift for the 22nd year of marriage. The name “spinel” is derived from the Latin word “spina,” meaning “thorn,” due to the gemstone’s structural shape.
Sardonyx: The Ancient August Birthstone
Sardonyx is the oldest of the three August birthstones, with a history that dates back more than 4,000 years. It is a type of chalcedony composed of alternating bands of sard (a reddish-brown chalcedony) and onyx (a black or white chalcedony). The name sardonyx is derived from its appearance, combining the characteristics of both sard and onyx.
During the Renaissance, sardonyx was worn by public speakers and orators for its power of eloquence. It was also believed to help single women attract their ideal partners and to promote happy marriages. The stone’s banded appearance and contrasting colors make it a distinctive and elegant gemstone.
Sardonyx is primarily sourced from India, where it is known for its good contrast between the different colored layers. Other sources include Brazil, Germany, Czechoslovakia, Madagascar, Uruguay, and the United States.
Geological Formation and Sources
Peridot: A Gem from the Earth and Beyond
Peridot is a silicate mineral that forms under high-pressure and high-temperature conditions deep within the Earth’s mantle. It is carried to the surface through volcanic activity, where it can be found in hardened lava flows. Peridot can also be found in meteorites, making it one of the few gemstones with an extraterrestrial origin.
The primary sources of peridot include Zabargad Island in the Red Sea, Myanmar, the United States (particularly in Arizona), and various locations in China and Africa. The color of peridot is determined by the amount of iron in its crystal structure. Stones with higher iron content tend to have a deeper green hue.
Peridot has a hardness of 6.5 to 7 on the Mohs scale, making it relatively durable but still susceptible to scratches. It has a refractive index of 1.65 to 1.69 and a specific gravity of 3.34. Peridot is known for its low birefringence and lack of pleochroism, which means it does not display different colors when viewed from different angles.
Spinels: Diverse and Resilient
Spinels are silicate minerals that form in igneous rocks, particularly in basaltic and gabbroic environments. They can also be found in metamorphic rocks and alluvial deposits. The diverse range of colors in spinels is due to the presence of different trace elements. For example, red and pink spinels owe their color to chromium, while blue spinels are colored by cobalt or iron.
The primary sources of spinel include Myanmar, Sri Lanka, Vietnam, Tanzania, and Pakistan. Myanmar is known for producing spinels with arresting colors like hot pink and red. Sri Lanka produces blue, pink, and purple spinels, particularly in the Central Highlands and the Ratnapura District. In Vietnam, the Luc Yen region produces spinels in deep red, purple, pink, vivid blue, violet, and violet-blue. In 2007, pinkish and orangy-red spinels were discovered in Tanzania.
Spinels have a hardness of 7.5 to 8 on the Mohs scale, making them quite durable. They have a refractive index of 1.718 to 1.762 and a specific gravity of 3.95 to 4.10. Spinels are known for their high luster and brilliance, which make them a popular choice for jewelry.
Sardonyx: A Banded Chalcedony
Sardonyx is a type of chalcedony, which is a microcrystalline variety of quartz. It forms in cavities within volcanic rocks and is often found in sedimentary deposits. The alternating bands of sard and onyx in sardonyx are the result of varying mineral compositions and environmental conditions during its formation.
The primary source of sardonyx is India, where it is known for its good contrast between the different colored layers. Other sources include Brazil, Germany, Czechoslovakia, Madagascar, Uruguay, and the United States. Sardonyx is often used in carved cameos and intaglios due to its durability and distinct banding.
Sardonyx has a hardness of 6.5 to 7 on the Mohs scale and a specific gravity of 2.58 to 2.64. It has a refractive index of 1.53 to 1.54 and is generally opaque or translucent. The stone’s banded appearance and contrasting colors make it a distinctive and elegant gemstone.
Gemological Properties
Peridot
Peridot is a silicate mineral with the chemical formula (Mg,Fe)₂SiO₄. It belongs to the olivine mineral group and is characterized by its vivid green color, which is caused by the presence of iron in its crystal structure. The color can vary from yellowish green to greenish yellow, depending on the amount of iron present.
Peridot has a hardness of 6.5 to 7 on the Mohs scale, making it relatively durable but still susceptible to scratches. It has a refractive index of 1.65 to 1.69 and a specific gravity of 3.34. Peridot is known for its low birefringence and lack of pleochroism, meaning it does not display different colors when viewed from different angles.
Peridot is typically found in volcanic rocks and meteorites, and it can also be found in metamorphic rocks and alluvial deposits. It is a popular gemstone for jewelry due to its vibrant color and affordability.
Spinels
Spinels are silicate minerals with the general chemical formula AB₂O₄, where A and B represent different metal ions. The diverse range of colors in spinels is due to the presence of different trace elements. For example, red and pink spinels owe their color to chromium, while blue spinels are colored by cobalt or iron.
Spinels have a hardness of 7.5 to 8 on the Mohs scale, making them quite durable. They have a refractive index of 1.718 to 1.762 and a specific gravity of 3.95 to 4.10. Spinels are known for their high luster and brilliance, which make them a popular choice for jewelry.
Spinels are typically found in igneous rocks, particularly in basaltic and gabbroic environments. They can also be found in metamorphic rocks and alluvial deposits. Spinels are often used in jewelry due to their durability and vibrant colors.
Sardonyx
Sardonyx is a type of chalcedony, which is a microcrystalline variety of quartz. It has the chemical formula SiO₂ and is composed of alternating bands of sard (a reddish-brown chalcedony) and onyx (a black or white chalcedony). The name sardonyx is derived from its appearance, combining the characteristics of both sard and onyx.
Sardonyx has a hardness of 6.5 to 7 on the Mohs scale and a specific gravity of 2.58 to 2.64. It has a refractive index of 1.53 to 1.54 and is generally opaque or translucent. The stone’s banded appearance and contrasting colors make it a distinctive and elegant gemstone.
Sardonyx is often used in carved cameos and intaglios due to its durability and distinct banding. It is typically found in volcanic rocks and sedimentary deposits. The primary source of sardonyx is India, where it is known for its good contrast between the different colored layers. Other sources include Brazil, Germany, Czechoslovakia, Madagascar, Uruguay, and the United States.
Symbolism and Metaphysical Beliefs
Peridot
Peridot has long been associated with positive energy, protection, and emotional healing. In ancient Egypt, it was believed to protect against nightmares and bring the wearer confidence, health, and positive energy. The stone was also used in religious and ceremonial contexts, particularly in church altars and clerical robes.
In modern times, peridot is believed to promote emotional healing and reduce stress. It is also associated with the heart chakra and is believed to help open the heart to love and compassion. Peridot is often used in jewelry and is believed to bring good fortune and prosperity.
Spinels
Spinels have a rich history of symbolism and metaphysical beliefs. In ancient times, they were believed to have protective and healing properties. They were often used in jewelry and amulets to protect the wearer from harm and to promote good health.
In modern times, spinels are believed to promote balance and harmony. They are associated with the heart and solar plexus chakras and are believed to help with emotional healing and self-confidence. Spinels are also believed to enhance creativity and passion.
Sardonyx
Sardonyx has long been associated with eloquence, success, and protection. In ancient times, it was believed to help public speakers and orators speak with clarity and confidence. It was also believed to help single women attract their ideal partners and to promote happy marriages.
In modern times, sardonyx is believed to promote success and ambition. It is associated with the root and sacral chakras and is believed to help with grounding and emotional stability. Sardonyx is also believed to enhance communication and help with decision-making.
Care and Cleaning
Peridot
Peridot is a relatively durable gemstone, but it is still susceptible to scratches and damage from harsh chemicals. To care for peridot jewelry, it is recommended to avoid exposure to abrasive materials and to clean it with a soft cloth and mild soap and water. Ultrasonic and steam cleaners should be used with caution, as they can cause damage to the stone.
Peridot should be stored separately from other gemstones to prevent scratches. It is also important to avoid exposing peridot to high heat, as this can cause it to lose its luster or become discolored.
Spinels
Spinels are quite durable and can be cleaned with a soft cloth and mild soap and water. They can also be cleaned with ultrasonic and steam cleaners, as they are resistant to damage from these methods. However, it is important to avoid exposure to harsh chemicals and abrasive materials.
Spinels should be stored separately from other gemstones to prevent scratches. They are also resistant to heat, but it is still recommended to avoid exposing them to high temperatures.
Sardonyx
Sardonyx is a durable gemstone that can be cleaned with a soft cloth and mild soap and water. It is also resistant to damage from ultrasonic and steam cleaners. However, it is important to avoid exposure to harsh chemicals and abrasive materials.
Sardonyx should be stored separately from other gemstones to prevent scratches. It is also important to avoid exposing sardonyx to high heat, as this can cause it to lose its luster or become discolored.
Conclusion
August birthstones—peridot, spinel, and sardonyx—offer a unique and diverse array of gemstones, each with its own distinct history, properties, and symbolism. Peridot, with its vibrant green color and cosmic origin, has been cherished for thousands of years. Spinel, once mistaken for ruby, has recently gained recognition as a valuable and versatile gemstone. Sardonyx, the oldest of the three, has a rich history of use in ancient civilizations and continues to be valued for its elegance and durability.
These gemstones not only serve as beautiful adornments but also carry deep cultural and symbolic meanings. Whether used in jewelry, as protective amulets, or as symbols of love and prosperity, peridot, spinel, and sardonyx continue to captivate and inspire those who wear them.