For those born in August, the choice of a birthstone is not limited to a single gem. The month is uniquely associated with three distinct official birthstones: peridot, spinel, and sardonyx. This trio offers a remarkable spectrum of color, history, and symbolism, reflecting the warmth and energy of summer. While peridot is often the most recognized, spinel carries a legacy of being mistaken for rubies, and sardonyx holds the title of the traditional August stone with a history stretching back millennia. This article delves into the geological origins, gemological properties, historical lore, and cultural significance of these three gems, providing a comprehensive guide for gemstone enthusiasts, collectors, and anyone seeking to understand the full depth of August's birthstones.
The American Gem Trade Association (AGTA) and Jewelers of America (JA) have officially recognized this trio, with sardonyx as the traditional stone, peridot as the official stone since 1912, and spinel added as a modern option in 2016. This expansion was driven by a desire to offer consumers greater variety in color, affordability, and availability. Each stone possesses its own unique identity, from peridot’s vibrant green to spinel’s versatile palette and sardonyx’s earthy bands. Understanding their individual stories allows one to select a gem that resonates not only aesthetically but also with personal energy and intention.
History and Lore
Peridot: The Ancient Gem of the Sun
Peridot has a storied history that dates back thousands of years, with its origins deeply rooted in ancient Egyptian culture. The oldest-recorded source of peridot is the Egyptian island of Zabargad in the Red Sea, which was a primary mining site for the gem. The word “peridot” is believed to derive from the Arabic faridat, meaning “gem,” though some sources suggest it may come from the Greek word peridona, meaning “giving plenty.” This latter namesake aligns with the gemstone’s historical associations with prosperity and good fortune.
Throughout history, peridot has often been confused with other gems due to its rich green hue. The Red Sea island of Topazios, a purported source of the name “topaz,” actually produced peridot. In Germany’s Cologne Cathedral, the Shrine of the Three Holy Kings is decorated with 200 carats of gems long believed to be emeralds, which are, in fact, peridot. Some historians even speculate that Cleopatra’s famous emerald collection may have been comprised of peridot. Ancient Egyptians revered peridot, believing it protected against nightmares and brought the wearer happiness and strength. Its connection to the sun was profound, with some cultures believing it was a gift from the sun god Ra, capable of warding off evil spirits and promoting healing.
Spinel: The Underappreciated Royal Gem
Spinel’s history is marked by a long period of being mistaken for other, more famous gemstones, particularly ruby. For centuries, red spinel was confused with ruby, leading to its underappreciation until recently. Some of the world’s most famous “rubies” are, in fact, spinel. The gem’s name is believed to come from the Latin spina, meaning “thorn,” possibly referring to the sharp crystals it forms. Despite being overlooked, spinel has a royal history, often adorning the crowns and jewelry of monarchs. Its recent addition to the official August birthstone list in 2016 reflects a growing recognition of its unique beauty and value, offering consumers an alternative to ruby with its own distinct character and history.
Sardonyx: The Traditional Stone of Strength
Sardonyx is the original August birthstone, with a history that dates back more than 4,000 years. This banded variety of chalcedony, composed of alternating layers of sard and onyx, has been used in jewelry and signet rings since ancient times. Its name is derived from the Greek words sardios (sard) and onyx (onyx), referring to its characteristic red-brown and black bands. Sardonyx was highly valued in ancient Rome and Greece, where it was used for cameos and intaglios, often depicting scenes of heroism and virtue. The stone was believed to bring stability, courage, and protection to the wearer. Its enduring appeal lies in its earthy, grounding energy and its role as a symbol of strength and enduring relationships.
Geological Formation and Sources
Peridot: A Gem from the Mantle and Meteorites
Peridot is the yellowish green to greenish yellow gem variety of the mineral olivine. Its formation is unique among gemstones, as it can be found in hardened lava that carried it from deep within Earth’s mantle. Peridot is also one of the few gems found in meteorites that traveled from outer space, adding to its mystique. The gem’s color comes from the presence of iron in its crystal structure, not from trace elements like most other gems, resulting in its naturally vibrant hue.
Major sources of peridot include: - Zabargad Island, Egypt: The oldest-recorded source. - China: A significant producer of peridot. - Myanmar (Burma): Known for high-quality peridot. - Pakistan: Produces peridot in the Kashmir region. - Tanzania: A source of peridot in East Africa. - Vietnam: Yields peridot in various shades. - United States: Peridot is found in Arizona, New Mexico, and Hawaii, often in volcanic regions.
Spinel: Formed in Metamorphic Environments
Spinel is a mineral species with the chemical formula MgAl₂O₄. It forms in metamorphic rocks, particularly in magnesium-rich limestones and in the contact zones between magma and host rocks. Spinel crystals can be found in a wide range of colors due to the presence of trace elements like iron, chromium, and cobalt. The most sought-after color is a vivid red, but it also occurs in pink, orange, purple, blue, green, and black.
Key sources of spinel include: - Myanmar (Burma): Historically the most famous source for red spinel, particularly from the Mogok region. - Tajikistan: Produces high-quality spinel, including the renowned Kuh-i-Lal deposit. - Sri Lanka: A source of spinel in various colors. - Vietnam: Yields spinel in the Luc Yen district. - Tanzania: Known for spinel in a range of hues. - Afghanistan: Produces spinel, including blue and pink varieties.
Sardonyx: A Banded Chalcedony
Sardonyx is a variety of chalcedony, which is a cryptocrystalline form of quartz. It is composed of alternating layers of sard (a reddish-brown chalcedony) and onyx (a black chalcedony). The bands are formed through the deposition of silica in volcanic rock cavities over time. Sardonyx is typically found in regions with volcanic activity or in sedimentary deposits.
Major sources of sardonyx include: - India: A primary source for sardonyx, particularly in the Deccan Plateau. - Brazil: Produces sardonyx in various colors. - United States: Found in states like Oregon and California. - Uruguay: A source of sardonyx. - Germany: Historically known for sardonyx deposits.
Gemological Properties
Peridot
- Chemical Composition: (Mg, Fe)₂SiO₄ (olivine)
- Crystal System: Orthorhombic
- Hardness: 6.5 to 7 on the Mohs scale
- Refractive Index: 1.65 to 1.69
- Specific Gravity: 3.34 to 3.37
- Color: Yellowish green to greenish yellow, ranging from bright lime to deep olive
- Clarity: Typically eye-clean, with inclusions common but often acceptable
- Cut: Often faceted to enhance its brilliance, but also cut into cabochons or beads
- Transparency: Transparent to translucent
Peridot’s hardness of 6.5 to 7 makes it relatively durable for everyday wear, though it can be susceptible to scratching if not handled with care. Its vibrant green color is consistent and does not fade with light exposure, making it a stable gem for jewelry.
Spinel
- Chemical Composition: MgAl₂O₄
- Crystal System: Cubic
- Hardness: 8 on the Mohs scale
- Refractive Index: 1.712 to 1.762
- Specific Gravity: 3.58 to 3.61
- Color: Wide range including red, pink, orange, purple, blue, green, and black
- Clarity: Often eye-clean, with some inclusions possible
- Cut: Excellent for faceting due to its high refractive index and dispersion
- Transparency: Transparent to translucent
Spinel’s hardness of 8 makes it one of the more durable gemstones, suitable for rings and daily wear. Its cubic crystal system gives it excellent light performance, and its color variety is unmatched among birthstones.
Sardonyx
- Chemical Composition: SiO₂ (quartz)
- Crystal System: Trigonal (cryptocrystalline)
- Hardness: 7 on the Mohs scale
- Refractive Index: 1.53 to 1.54
- Specific Gravity: 2.65
- Color: Bands of red-brown (sard) and black (onyx), sometimes with white
- Clarity: Opaque to translucent, with distinct banding
- Cut: Often carved into cameos or cut as cabochons to showcase banding
- Transparency: Translucent to opaque
Sardonyx’s hardness of 7 makes it durable, but its opaque nature limits its use to certain jewelry styles. The banding is its defining feature, making it ideal for carved pieces and statement jewelry.
Symbolism and Metaphysical Beliefs
Peridot: The Stone of Positivity and Abundance
Peridot is associated with the Heart Chakra, promoting emotional balance, joy, and the release of negative patterns. Its bright green color is linked to growth, renewal, and the energy of the sun. Historically, it was believed to bring happiness, strength, and protection against nightmares. In modern metaphysical practices, peridot is said to boost mood, confidence, and attract abundance. It is often recommended for those seeking to open their heart to love and experience a sense of upliftment.
Spinel: The Stone of Renewal and Inspiration
Spinel is considered a high-energy stone that promotes renewal, inspiration, and vitality. Its wide range of colors allows it to be associated with different chakras and intentions. Red spinel is linked to the Root Chakra, offering grounding and stability, while blue spinel is associated with the Throat Chakra, enhancing communication. Spinel is believed to restore energy, inspire hope, and provide encouragement during difficult times. Its historical association with royalty adds a sense of power and prestige to its symbolism.
Sardonyx: The Stone of Strength and Protection
Sardonyx is deeply connected to the Earth, offering grounding and protective energy. Its banded structure symbolizes stability, courage, and enduring strength. Historically, it was used to protect against negative forces and to promote steadfast relationships. In modern crystal healing, sardonyx is said to enhance willpower, discipline, and self-confidence. It is often chosen for its ability to provide emotional stability and support during times of stress or change.
Care and Cleaning
Peridot
Due to its hardness of 6.5 to 7, peridot is relatively durable but can be scratched by harder materials. It is best cleaned with warm, soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning, as sudden temperature changes can cause fractures. Store peridot jewelry separately to prevent scratching by other gems.
Spinel
Spinel’s hardness of 8 makes it one of the more resilient gemstones. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe, but caution is advised if the stone has fractures. Steam cleaning is also acceptable. Store spinel jewelry in a fabric-lined box to protect it from scratches.
Sardonyx
Sardonyx, with a hardness of 7, is durable but can be damaged by harsh chemicals. Clean it with warm, soapy water and a soft brush. Avoid ultrasonic cleaners, as the vibrations may loosen any settings. Do not use steam or high heat. Store sardonyx jewelry separately to prevent scratches from harder materials.
Conclusion
The three birthstones of August—peridot, spinel, and sardonyx—offer a rich tapestry of history, science, and symbolism. Peridot, with its solar energy and ancient Egyptian origins, brings joy and abundance. Spinel, once mistaken for ruby, now shines as a versatile and durable gem of renewal. Sardonyx, the traditional stone, provides grounding strength and protection with its earthy bands. Together, they reflect the warmth and vitality of summer, giving August-born individuals a choice of gems that align with their personal style and spiritual intentions. Whether selected for its color, history, or metaphysical properties, each of these stones carries a legacy of beauty and significance that makes it a timeless treasure.