August is unique among the months of the year for its trio of birthstones—Peridot, Sardonyx, and Spinel—each with its own rich history, captivating properties, and symbolic significance. This month, originally named Sextillus in ancient Rome and later renamed in honor of Emperor Augustus, is also the month with the highest number of births in the United States. As a result, it has been historically and culturally significant, and its birthstone tradition reflects this importance. From medieval European traditions to modern designations by the American Gem Trade Association and the Jewelers of America, the August birthstones have evolved to reflect both ancient lore and contemporary gemological practices.
This article delves into the origins, properties, symbolism, and care of each of these three gemstones, offering a comprehensive resource for gemstone enthusiasts, jewelry buyers, and students of gemology.
History and Lore
The tradition of birthstones is deeply rooted in history and has evolved over centuries, with various cultures assigning specific gemstones to each month. The earliest known reference to gemstones associated with months comes from the Breastplate of Aaron, described in the Book of Exodus in the Bible. This sacred artifact, worn by the High Priest of the Israelites, was adorned with twelve gemstones, each representing one of the twelve tribes of Israel. Over time, these stones were associated with the zodiac signs and the months of the year, forming the foundation of the birthstone tradition.
The concept of birthstones as we know it today began to take shape in the 15th century in Poland and Germany, where the practice of assigning gemstones to each month became more formalized. By the 19th and 20th centuries, different countries had developed their own variations of the birthstone calendar, influenced by local traditions, mineral availability, and cultural beliefs.
August is particularly notable for having three official birthstones: Peridot, Sardonyx, and Spinel. This distinction was made to accommodate the historical confusion between similar-colored stones and to reflect a more modern and inclusive approach to gemstone selection. Initially, Sardonyx was the sole August birthstone, but due to its frequent misidentification with Peridot, the latter was added as a second gemstone in the 20th century. Finally, in 2016, Spinel was introduced as the third official birthstone for August, enriching the month's gemstone legacy with a vibrant and versatile stone.
Geological Formation and Sources
Peridot
Peridot is a variety of the mineral olivine, composed primarily of magnesium iron silicate (Mg₁.₀₋₂.₀Fe₀.₀₋₁.₀SiO₄). It forms in mafic and ultramafic igneous rocks, typically in basaltic lava flows or in metamorphic rocks under high-pressure conditions. Peridot is found in a range of locations around the world, including:
- Burmah (Myanmar)
- Arizona and New Mexico (USA)
- Brazil
- Madagascar
- Nigeria
Peridot's color, which ranges from yellowish-green to olive-green, is due to the presence of iron in its chemical structure. It has a Mohs hardness of 6.5 to 7, making it relatively durable but not as tough as gems like diamond or ruby. Its specific gravity is 3.34, and it has a refractive index of 1.65 to 1.69, contributing to its lively luster.
Sardonyx
Sardonyx is a banded variety of chalcedony, which is a form of microcrystalline quartz. It is composed of silica (SiO₂) and is known for its distinct banding patterns, typically alternating between red or brown (sard) and white (onyx) tones. Sardonyx forms in sedimentary rock deposits, often in cavities or veins, where it crystallizes from silica-rich solutions over time.
Key sources of sardonyx include:
- India
- Brazil
- Ethiopia
- Madagascar
- Mexico
The stone has a Mohs hardness of 6.5 to 7, similar to peridot, and is valued for its resistance to wear and tear. Its specific gravity is around 2.60, and it does not have a refractive index due to its amorphous structure.
Spinel
Spinel is a oxide mineral with the chemical formula MgAl₂O₄, though it can occur in a wide range of colors depending on trace elements. The most notable varieties include red spinel, often mistaken for ruby, and blue, pink, and green spinel. Spinel forms in metamorphic and igneous rocks, particularly in marble deposits and basaltic lava flows.
Prominent sources of spinel include:
- Afghanistan
- Burmah (Myanmar)
- Vietnam
- Tanzania
- Madagascar
Spinel has a Mohs hardness of 8, making it one of the most durable of the August birthstones. It has a refractive index of 1.718, and its specific gravity ranges from 3.60 to 4.00, depending on its composition.
Gemological Properties
Peridot
| Property | Value |
|---|---|
| Chemical Formula | Mg₁.₀₋₂.₀Fe₀.₀₋₁.₀SiO₄ |
| Color | Yellowish-green to olive-green |
| Hardness (Mohs) | 6.5 – 7 |
| Specific Gravity | 3.34 |
| Refractive Index | 1.65 – 1.69 |
| Birefringence | 0.035 – 0.038 |
| Luster | Vitreous |
| Cleavage | Perfect in one direction |
| Translucency | Transparent to translucent |
Peridot is known for its vibrant color and affordability, making it a popular choice for jewelry. It is often cut into round, oval, or emerald shapes to showcase its brilliance and clarity.
Sardonyx
| Property | Value |
|---|---|
| Chemical Formula | SiO₂ |
| Color | Red, brown, and white banded patterns |
| Hardness (Mohs) | 6.5 – 7 |
| Specific Gravity | 2.60 |
| Luster | Waxy to vitreous |
| Cleavage | None |
| Translucency | Translucent to opaque |
Sardonyx is prized for its distinct banding and durability, making it ideal for cabochons, beads, and carved cameos. It is often used in intaglio and cameo work, where its contrasting colors highlight intricate designs.
Spinel
| Property | Value |
|---|---|
| Chemical Formula | MgAl₂O₄ |
| Color | Red, blue, pink, green, orange, etc. |
| Hardness (Mohs) | 8 |
| Specific Gravity | 3.60 – 4.00 |
| Refractive Index | 1.718 |
| Luster | Vitreous |
| Cleavage | None |
| Translucency | Transparent to translucent |
Spinel is notable for its wide color range and exceptional brilliance, often outshining other stones of similar hardness. It is commonly cut into round, cushion, or princess shapes to enhance its fire and luster.
Symbolism and Metaphysical Beliefs
Peridot
Peridot is regarded as a stone of transformation and self-forgiveness. In ancient Egypt, it was known as the "evening emerald" and was believed to have been formed from solidified sunlight. It was used in protective amulets and was thought to bring good fortune and ward off nightmares.
Modern metaphysical beliefs associate peridot with emotional healing, clarity of mind, and personal responsibility. It is said to help individuals acknowledge their mistakes and grow from them, making it a powerful tool for self-improvement and emotional balance.
Sardonyx
Sardonyx has long been valued for its protective and grounding properties. In ancient Rome, it was used in amulets and signet rings, believed to ward off envy and bring courage. It is also associated with self-confidence, optimism, and joy.
Metaphysically, sardonyx is thought to enhance communication, promote emotional stability, and support personal willpower. It is often used in rituals and meditation to align the body's energy and strengthen the spirit.
Spinel
Spinel is a stone of love, protection, and courage. In ancient times, it was often mistaken for ruby and was highly prized for its deep red color and brilliance. In India, it was called "Balas Ruby" after the Balas mountains, where it was mined.
Spinel is believed to enhance vitality, strengthen the heart, and promote emotional healing. It is also associated with passion, creativity, and spiritual awakening. Different colors of spinel carry distinct meanings:
- Red – Passion, courage, vitality
- Blue – Clarity, intuition, calmness
- Pink – Love, compassion, nurturing
Care and Cleaning
Proper care is essential to preserve the beauty and longevity of August's birthstones. Here are some specific care instructions for each gemstone:
Peridot
- Avoid exposure to heat and sudden temperature changes, as peridot has a perfect cleavage and can be prone to chipping.
- Clean with warm, soapy water and a soft cloth. Use a soft-bristled brush to remove dirt from crevices.
- Store peridot separately from harder gemstones to prevent scratches.
Sardonyx
- Sardonyx is relatively durable, but it can be dull or scratched by harder materials.
- Clean with a soft cloth and mild soap. Avoid harsh chemicals or abrasive cleaners.
- Polish with a soft cloth to maintain its luster.
Spinel
- Spinel is very durable and can be cleaned with ultrasonic or steam cleaners, though steam cleaning should be avoided for heat-sensitive spinels.
- Use a soft brush and warm soapy water for routine cleaning.
- Store spinel away from abrasive materials to avoid scratches.
Conclusion
August's trio of birthstones—Peridot, Sardonyx, and Spinel—offer a rich tapestry of history, symbolism, and beauty. From the fiery green of peridot to the banded elegance of sardonyx and the vibrant hues of spinel, these gemstones have captivated people for centuries. Their inclusion as August's birthstones reflects both ancient traditions and modern innovations, making them a unique and meaningful choice for jewelry and personal adornment.
Whether chosen for their metaphysical properties, aesthetic appeal, or historical significance, these stones serve as a celebration of the month's legacy and the enduring fascination with gemstones. For those born in August, these gemstones offer not only a personal connection to their birth month but also a symbol of strength, protection, and transformation.