Introduction
August is one of the few months in the birthstone calendar that is represented by three distinct gemstones—peridot, spinel, and sardonyx. Among these, peridot has risen in prominence and is now widely celebrated as the primary birthstone for August, valued for its radiant color and rich history. While peridot is recognized for its vibrant green hue, its unique gemological qualities and origins set it apart from the many other green gemstones in the world.
This article delves into the color science behind peridot, exploring how it stands out on the gemological scale and in cultural perception. Drawing from the information in the provided sources, it also touches on spinel and sardonyx, the two other August birthstones, to form a comprehensive understanding of the variety and symbolism associated with this month. Through historical context, scientific properties, cultural meaning, and practical care advice, this piece aims to serve as an authoritative guide for gemstone connoisseurs and jewelry enthusiasts.
History and Lore
The Ancient Roots of Peridot
Peridot has been cherished for thousands of years. Known in ancient Egypt as the “Gem of the Sun”, it was believed to have been formed from the light of the sun itself. Egyptian miners extracted peridot from the island of Topazios (now known as Zabargad) in the Red Sea, where it glowed under the desert sun. Ancient texts suggest that peridot was considered a guardian gem, helping wearers ward off nightmares and bringing them confidence and good fortune.
In medieval Europe, peridot continued to be associated with spiritual and protective qualities. It was often used in churches and royal jewelry, with many believing that the stone could protect against evil spirits. The gem was also used in signet rings and jewelry pieces for nobility.
Renaissance to Present
With the Renaissance came a renewed interest in gemstones, and peridot became a popular choice among European royalty and wealthy merchants. Though it was occasionally mistaken for emerald or topaz, its clarity and affordability made it a valuable alternative.
A historic instance cited in the literature is the Shrine of the Three Holy Kings in the Cologne Cathedral, Germany, which was built in the 12th century. The shrine was adorned with 200 carats of gems, originally thought to be emeralds, but later found to be peridot. This highlights how the stone, though less well-known in some periods, played a significant role in historical ornamentation and symbolism.
Peridot's modern resurgence in popularity, particularly in jewelry, began in the late 20th and early 21st centuries. Thanks to design innovation and consumer demand for bright, natural colors, peridot gained notoriety once again—especially in the form of large, eye-catching pieces.
Geological Formation and Sources
How Peridot is Formed
Peridot is the only gemstone that forms in the Earth’s mantle, originating under extremely high temperatures and pressures. As one of the most abundant minerals in the Earth’s interior, peridot is a rare, gem-quality variety of olivine, a mineral composed of iron and magnesium silicate.
The formation process of peridot involves the solidification of magma and, more recently, the movement of volcanic activity, which brings the stone to the surface. It is not uncommon for peridot to be found in volcanic rocks, such as basalt, where it is cooled gradually to form into well-defined crystals.
Peridot is also occasionally found in meteorites, most notably in the Pallasite meteorites, a rare type containing a mixture of olivine and iron nickel crystals. This extraterrestrial origin adds to the mystique and allure of the gemstone.
Global Sources of Peridot
Peridot is naturally found in various locations around the world, though not all provide gem-quality material. Some of the key sources mentioned in the provided literature include:
- Arizona, USA: Arizona (particularly San Carlos, Apache County, and Mohave County) is currently the most important commercial source of peridot. The deposits here yield high-quality, bright green stones in a range of sizes.
- Hawaii (USA): Known as “Pele’s Tears” after the Hawaiian fire goddess Pele, peridot in Hawaii is associated with volcanic activity and is often used in regional jewelry.
- Pakistan and Myanmar: These regions are minor but important contributors of fine-quality peridot with a bright green to olive-green hue.
- Red Sea Islands (Zabargad): The ancient source is now relatively inactive, but it remains historically significant.
- China and Afghanistan: Both countries also yield commercial quantities of peridot, though the color and clarity can vary.
Though lab-created versions of peridot (and other colorful gems like spinel) are available, the natural formation of peridot in such extreme settings makes it a truly extraordinary natural gem.
Gemological Properties
Color
Color is the most distinctive feature of peridot and is a result of iron content within the olivine structure. The only consistent color in peridot is green, which ranges through various shades:
- Yellowish-green
- Olive-green
- Chartreuse
- Deep green
It is one of the few natural gemstones that do not display a variety of colors inside the same species. The vibrant green is so vivid that it often stands out among other colored gems, giving it a one-of-a-kind identity.
Clarity
Natural peridot is usually included due to its mafic mineral origins, but because it forms in volcanic conditions, these inclusions are typically internal and not detrimental to beauty or value. The best-quality peridot is free of visible inclusions to the naked eye, with VS (Very Slightly Included) clarity being typical for high-grade specimens.
Hardness and Durability
On the Mohs scale, peridot has a hardness rating of 6.5 to 7, which places it between apatite and quartz. This makes it relatively easy to scratch, so it is not the best choice for daily wear, particularly in rings. Scratches and abrasions can occur if not handled with care.
Peridot also has perfect cleavage, which means it can split easily along internal planes if struck from the right angle. This makes it less suitable for hard-use settings like rings and bracelets unless it is set cautiously in a protective way.
Specific Gravity and Refractive Index
Peridot has a specific gravity of 3.3 to 3.5, meaning it is a relatively dense gemstone for its size, due to its high iron content.
The refractive index of peridot ranges between 1.65 and 1.81, depending on its composition, contributing to its glassy luster and brilliance when cut properly.
Chemical Composition and Crystal Structure
Peridot’s chemical formula is (Mg,Fe)₂SiO₄, and it belongs to the olivine group of minerals.
Its crystal system is orthorhombic, and the gem is often cut in brilliant or mixed styles to bring out its fire and color. Facet design can significantly influence the stone’s optical performance, with the best faceting maximizing its brightness and color return.
Symbolism and Metaphysical Beliefs
Ancient and Cultural Symbolism
As touched on earlier, peridot was cherished not only for its color but also for its protective and spiritual properties.
In ancient times, it was believed to help the wearer sleep soundly and ward off nightmares. Some legend says that if placed under the pillow, peridot would protect the dreamer from evil.
In Celtic and other historical cultures, peridot was associated with renewal, fertility, and courage. It was worn by travellers and warriors for protection during long journeys or battles.
Modern and Metaphysical Use
Modern interpretations of peridot still associate it with positivity, making it a symbol of joy, peace, and balance.
In metaphysical practices, peridot is said to have the power to boost self-esteem, promote healing after heartbreak, and attract prosperity. It is believed to be a stone of confidence and spiritual insight, helping the wearer to embrace change and remain grounded.
Peridot is sometimes referred to as the “evening gem” because it is said to emit a soft glow when worn at night, believed to help maintain peace and tranquility.
Comparison with Similar Gemstones
Peridot vs. Spinels
Though spinel is a newer addition to August’s birthstone list (added in 2016), it is a close relative in color and utility. In red and purple hues, spinel resembles ruby and sapphire, and unlike its rarer counterparts, it is more affordable and durable.
Spinel rates 8 on the Mohs scale, making it far more suitable for everyday wear than peridot.
| Feature | Peridot | Spinel |
|---|---|---|
| Hardness (Mohs) | 6.5–7 | 8 |
| Color Range | Only green | Red, pink, purple, blue, black |
| Inclusions | Often included | Often eye-clean or VVS |
| Rarity | Relatively common | Rare in fine colors |
| Value (per ct.) | Moderate | High |
In jewelry, spinel offers broader versatility in color and setting, though peridot stands out in its uniquely vibrant and consistent green hue.
Care and Maintenance
Given the relatively soft and fragile nature of peridot, proper care and cleaning are essential to preserving its beauty and value.
Cleaning Methods
- Avoid ultrasonic cleaners: Due to its perfect cleavage and inclusions, peridot may be damaged by vibrations.
- Steam cleaning should also be used with caution.
- The best method for cleaning peridot is warm soapy water with a soft cloth or brush, then rinse and dry with a lint-free towel.
Storage Practices
Peridot should be stored in a soft-lined jewelry box or velvet pouch, separate from other gemstones, to prevent scratches and damage. Since it is prone to cleavage and impact, it should also be stored away from sharp or heavy objects.
Conclusion
Peridot, with its vibrant green color and rich historical importance, is more than just the jewel of August—it is a gemstone of transformation, renewal, and resilience. From its fiery extraterrestrial origin to its role in ancient Egyptian traditions, the stone embodies the duality of light and darkness, making it a powerful symbol for wearers and collectors alike.
While spinel and sardonyx add to the colorful diversity of August birthstones, peridot remains the most uniquely green and spiritually symbolic among them. Whether chosen for its beauty, history, or mystical properties, it makes a valuable and meaningful gift for anyone born in August.
As one of the few gemstones that cannot be confused with another in color, and with such a distinct geological and cultural background, peridot stands not only as a birthstone, but as a celebration of the vibrant, life-affirming spirit of late summer.