For those born in August, the month is graced with not one, but three stunning birthstones: Peridot, Sardonyx, and Spinel. Each of these gemstones carries a unique legacy, distinct physical and chemical properties, and a rich tapestry of historical and cultural significance. From the deep green glow of Peridot, formed in the Earth’s mantle, to the bold striped layers of Sardonyx and the vibrant brilliance of Spinel, August’s birthstones offer a diverse and compelling selection for jewelry and personal adornment. This article delves into the geological origins, symbolic meanings, and practical care of these remarkable stones, drawing from authoritative sources to provide a comprehensive and factual account.
Introduction
August is one of the few months with multiple traditional and modern birthstones, reflecting the diversity and richness of gemstone history. The primary August birthstone is Peridot, a gemstone of striking green hues and deep historical roots. Sardonyx, with its alternating bands of sard and onyx, is the oldest August birthstone and was historically significant in religious and ceremonial contexts. Spinel, the newest of the three to be designated as an August birthstone in 2016, has long been mistaken for ruby or sapphire due to its brilliant colors and luster. Together, these gemstones represent not only beauty but also symbolic power and cultural heritage.
This article explores the origins, properties, symbolism, and care of each of these stones, supported by sources that span gemological data, historical accounts, and cultural lore. It is designed for enthusiasts, jewelry buyers, and gemology students who seek to understand the deeper significance and scientific properties of August’s birthstones.
History and Lore
Peridot: From the Earth’s Mantle to the Surface
Peridot is one of the few gemstones that originate not in the Earth’s crust but in its mantle, the layer beneath the crust. This deep formation, under intense pressure and heat, is shared only with diamonds. Peridot is formed when magma, carrying the mineral forsterite (a type of olivine), cools and solidifies on the surface. In rare cases, Peridot is also found in meteorites, such as the Jepara meteorite discovered on Java, Indonesia.
The name "Peridot" likely derives from the Arabic word faridat, meaning “gem,” though this etymology is not definitively confirmed. Peridot has long been associated with growth, prosperity, love, and protection, and it was traditionally given as a gift to celebrate a 16th wedding anniversary.
Peridot’s history is steeped in myth and symbolism. It was once believed to be a “sun stone,” associated with the warmth and energy of the sun. In ancient Egypt, Peridot was considered a sacred gem, and it was even used in jewelry by the Pharaohs. The gem’s green color, which ranges from pale yellow-green to deep olive, is caused by the presence of iron in its chemical composition.
Sardonyx: A Stone of Stripes and Strength
Sardonyx is an ancient gemstone, known for its striped patterns of sard and onyx. Sard is a type of chalcedony with a reddish-brown to dark orange hue, while onyx is typically white or black. This alternating banding gives Sardonyx a distinctive, eye-catching appearance.
Sardonyx has a long history of use in amulets, cameos, and seals, particularly in ancient Greece and Rome, where it was believed to bring victory in battle and enhance communication skills. The stone was also referenced in the Bible, where it was one of the foundation stones of Jerusalem and one of the gems on the high priest’s breastplate (Breastplate of Aaron) in the Book of Exodus.
Sardonyx is known for symbolizing strength, courage, and protection. It was often worn as a talisman for travelers and warriors, and it was used in engraved seals for administrative and legal purposes. The stone’s affordability and durability made it a popular choice for jewelry, especially pendants and rings.
Spinel: The Forgotten Gemstone
Spinel was once mistaken for ruby and sapphire due to its vibrant colors and brilliance. It wasn’t until the 19th century that gemologists distinguished Spinel as a separate mineral species. Spinel can appear in a wide range of colors, including red, blue, pink, and even black, making it a versatile and striking gemstone.
Spinel was officially recognized as an August birthstone in 2016, adding a new dimension to the month’s traditional selections. The stone is valued for its brilliance and clarity, often rivaling that of corundum (the mineral group that includes ruby and sapphire). Spinel’s hardness on the Mohs scale is 8, making it a durable and practical choice for everyday jewelry.
Spinel has a rich historical legacy, with many famous “rubies” in royal collections actually being Spinel. One notable example is the “Black Prince’s Ruby,” set in the British Crown Jewels, which is, in fact, a large red Spinel. The stone’s deep red color and high refractive index make it an attractive and affordable alternative to ruby for those who appreciate bold, vibrant gems.
Geological Formation and Sources
Peridot
Peridot forms in ultramafic rocks, which are rich in magnesium and iron and are typically found in the Earth’s mantle. These rocks are brought to the surface through volcanic activity, where the minerals within them cool and solidify. The iron content in Peridot is responsible for its green color, with higher iron content producing darker shades.
Peridot is found in several parts of the world, including:
- Arizona (USA) – Known for its high-quality Peridot, particularly in the San Carlos Apache Reservation
- Madagascar – A major producer of Peridot
- Brazil – Produces a wide range of Peridot colors
- Egypt – Historical source of Peridot, especially during the Pharaonic era
- India – A key source of Peridot in both historical and modern times
Peridot is relatively common compared to other gemstones, though high-quality stones with a pure green color and minimal inclusions can be rare and valuable.
Sardonyx
Sardonyx is a chalcedony, a type of microcrystalline quartz. It is formed through sedimentary processes, where layers of sard and onyx alternate over time. Sardonyx is often mined in India, where the most distinct and well-defined banding is found.
Other notable sources of Sardonyx include:
- Brazil – Known for producing Sardonyx with bold, contrasting bands
- Germany and Czech Republic – Historical centers for Sardonyx carving and engraving
- Uruguay and United States – Also produce Sardonyx with good color contrast
Sardonyx is relatively abundant and inexpensive, making it a popular choice for carved seals, cameos, and pendants.
Spinel
Spinel is formed in mafic igneous rocks, particularly in basaltic and gabbroic formations. It can also be found in metamorphic rocks and sedimentary deposits. Spinel is often associated with other gemstones such as corundum and garnet, and it is sometimes found in the same geological environments as tourmaline and topaz.
Key sources of Spinel include:
- Afghanistan – A major source of high-quality red and blue Spinel
- Sri Lanka – Known for producing vibrant-colored Spinel
- Myanmar (Burma) – Produces some of the most valuable red Spinel
- Madagascar – A growing source of Spinel in recent years
- Vietnam and Tanzania – Also contribute to the global supply of Spinel
Spinel is relatively rare, especially in deep red and cobalt blue colors. The rarity of certain colors and the brilliance of the gem make Spinel a highly sought-after gemstone.
Gemological Properties
Peridot
Peridot is a gem-quality form of forsterite, a member of the olivine mineral group. Its physical and optical properties include:
- Color: Green, ranging from yellow-green to olive green (due to iron content)
- Hardness: 6.5 to 7 on the Mohs scale, relatively durable but not as hard as corundum (9) or diamond (10)
- Refractive Index: 1.65 to 1.69
- Birefringence: 0.035 to 0.038, visible in some specimens
- Specific Gravity: 3.34
- Crystal System: Orthorhombic
- Luster: Vitreous (glassy)
- Transparency: Usually transparent to translucent
- Inclusions: Commonly contains two-phase inclusions, consisting of forsterite and spinel crystals
Peridot is not found in any color other than green, making it unique among gemstones. Its glassy luster and high dispersion give it a lively appearance, especially when cut properly.
Sardonyx
Sardonyx is a banded chalcedony, composed of alternating layers of sard and onyx. Its properties include:
- Color: Alternating bands of reddish-brown to orange (sard) and white to black (onyx)
- Hardness: 6.5 to 7 on the Mohs scale
- Refractive Index: 1.53 to 1.54
- Luster: Waxy to vitreous
- Transparency: Translucent to opaque
- Inclusions: Typically clean, but may show banding patterns
Sardonyx is durable enough for everyday wear, especially in pendants and rings. It is often carved or engraved, with the contrasting bands making it ideal for cameo and intaglio work.
Spinel
Spinel is a garnet-group mineral, though it is not technically a garnet. Its properties include:
- Color: Available in red, blue, pink, orange, and black, among others
- Hardness: 8 on the Mohs scale, highly durable
- Refractive Index: 1.718 to 1.732
- Luster: Vitreous (glassy)
- Transparency: Usually transparent to translucent
- Inclusions: Often clean, though some may contain two-phase inclusions
- Crystal System: Cubic
Spinel is known for its brilliance and clarity, with a high refractive index that gives it a sparkling appearance. Its hardness makes it suitable for rings and bracelets, and its variety of colors allows for versatile jewelry design.
Symbolism and Metaphysical Beliefs
Peridot
Peridot has long been associated with positive energy, protection, and prosperity. Ancient Egyptians believed that Peridot could ward off nightmares and negative spirits, and it was often placed in tombs to guide the soul to the afterlife. The stone was also thought to enhance love and loyalty, making it a popular choice for engagement rings and wedding jewelry.
In modern metaphysical traditions, Peridot is believed to stimulate personal growth and self-confidence. It is also associated with healing properties, particularly for the digestive and circulatory systems. Some practitioners use Peridot in crystal healing to balance the chakras and promote emotional well-being.
Sardonyx
Sardonyx has been used for centuries as a protective and communicative stone. In ancient times, it was believed to enhance courage and strength, particularly in times of war or conflict. It was also associated with honesty and clarity, making it a popular choice for leaders and public speakers.
In modern crystal healing, Sardonyx is believed to ground and stabilize the emotions, helping to reduce anxiety and stress. It is also used to promote self-discipline and focus, making it a helpful stone for those seeking to achieve goals or maintain productivity.
Spinel
Spinel is considered a stone of passion and vitality. In ancient times, it was believed to enhance the power of love and relationships, and it was often used in engagement rings and love charms. The stone was also associated with strength and endurance, particularly in combat and physical challenges.
In modern metaphysical beliefs, Spinel is believed to stimulate the heart and bring joy to the soul. It is also associated with healing and regeneration, particularly for the nervous system and the skin. Some practitioners use Spinel in energy work to balance the chakras and promote emotional healing.
Care and Cleaning
Proper care and cleaning are essential for maintaining the beauty and longevity of August birthstone jewelry. Each gemstone has specific requirements due to its hardness, durability, and sensitivity to chemicals and heat.
Peridot
Peridot has a hardness of 6.5 to 7, which makes it relatively durable but not as tough as corundum or diamond. It is sensitive to heat and sudden temperature changes, so it should not be cleaned with steam or ultrasonic cleaners, as these can cause cracking or chipping.
To clean Peridot jewelry:
- Use mild soap and warm water
- Gently brush the gemstone with a soft-bristled brush
- Rinse thoroughly and dry with a soft cloth
Peridot should also be stored separately from harder gemstones to avoid scratching.
Sardonyx
Sardonyx is a hard and durable stone, with a hardness of 6.5 to 7. It is not sensitive to heat or chemicals, making it easier to clean than Peridot.
To clean Sardonyx jewelry:
- Use mild soap and warm water
- Brush gently with a soft-bristled brush
- Rinse and dry with a soft cloth
Sardonyx can be cleaned with an ultrasonic cleaner, but it is best to avoid steam cleaning, as the stone is porous and can absorb water.
Spinel
Spinel has a hardness of 8, making it very durable and suitable for everyday wear. It is resistant to heat and chemicals, making it easier to clean than Peridot.
To clean Spinel jewelry:
- Use mild soap and warm water
- Brush gently with a soft-bristled brush
- Rinse and dry with a soft cloth
- Ultrasonic and steam cleaning are generally safe for Spinel
Spinel should be stored in a dry, cool place to prevent any potential damage.
Conclusion
The August birthstones—Peridot, Sardonyx, and Spinel—offer a rich and diverse selection of gemstones, each with its own unique history, properties, and symbolism. From the deep green glow of Peridot to the bold striped patterns of Sardonyx and the vibrant brilliance of Spinel, these stones reflect the natural beauty and cultural richness of the world of gemstones.
Whether you are an August-born individual, a gemstone enthusiast, or a jewelry buyer, understanding the properties, history, and care of these stones can enhance your appreciation and enjoyment of them. These gemstones not only serve as beautiful adornments but also as symbols of strength, protection, and prosperity.
By selecting and caring for your August birthstone jewelry with care, you can preserve its beauty and significance for many years to come. Whether you choose Peridot for its sun-like glow, Sardonyx for its striking patterns, or Spinel for its brilliant colors, you are investing in a gemstone with a rich legacy and a timeless appeal.