Spinel, Peridot, and Sardonyx: A Trio of August Birthstones

August boasts a unique distinction among the calendar months – not one, but three recognized birthstones: peridot, spinel, and sardonyx. These gemstones, each with its own history, geological origins, and symbolic meaning, offer a diverse palette of color and character for those born under the August sun. While peridot and sardonyx have long-standing associations with the month, spinel is a more recent addition, officially recognized by the American Gem Trade Association (AGTA) and Jewelers of America as a modern August birthstone. This expansion of the birthstone list reflects a growing interest among gem enthusiasts in a wider range of options.

A Historical Perspective

The history of these three stones varies considerably. Sardonyx holds the longest documented association, appearing in ancient texts like the Bible as one of the stones in the high priest’s breastplate and as a foundational stone of Jerusalem. Its use dates back to ancient times, signifying its early importance in both religious and ornamental contexts. Peridot’s history is somewhat intertwined with that of topaz; historical texts often used the name “topaz” to refer to what is now known as peridot, particularly amber to yellow-green varieties. The island of Topazios, however, did not actually yield true topaz, further complicating the historical record.

Spinel’s history is marked by a long period of mistaken identity. For centuries, it was frequently misidentified as ruby, appearing in the crown jewels of various nations under the guise of its more valuable counterpart. It wasn’t until 1783 that spinel was scientifically distinguished from corundum (ruby and sapphire), revealing its unique chemical composition of magnesium aluminum oxide, differing from ruby’s aluminum oxide structure. Despite this late formal recognition, spinel has a rich, albeit often unacknowledged, history within royal collections.

Geological Origins and Sources

Each of these August birthstones originates from distinct geological environments. Peridot is known for its formation in the Earth’s mantle and is brought to the surface through volcanic activity. Historically, Egypt was a primary source, and it is believed to have adorned the jewelry of Queen Cleopatra VII. Today, peridot is also found in Hawaii, where it is considered the “tears of Pele,” the volcanic goddess, and in Myanmar and Vietnam, with Vietnamese peridot being particularly prized for its varied shades of green.

Spinel’s origins are diverse, occurring in metamorphic rocks and alluvial deposits. While specific source information within the provided materials is limited, its presence in historical royal jewelry suggests origins in regions known for ruby and sapphire mining, as it was often found alongside these gems.

Sardonyx, a variety of chalcedony, is found in India, Brazil, Uruguay, the United States, and Germany. It is characterized by its reddish-brown color and white banding, a result of the layering of different forms of silica during its formation.

Gemological Properties

The gemological properties of these three birthstones differ significantly, contributing to their unique appearances and values. Peridot is predominantly a light green color, though shades ranging to yellowish-green and brown are also found. The intensity of the green color is directly related to the amount of iron present in the stone; more iron results in a more vivid and valuable gem.

Spinel exhibits a wider range of colors, including red, yellow-orange (rubicelle), purple (almandine), blue (sapphirine), and green (chlorospinel). This variety contributes to its appeal as a modern birthstone.

Sardonyx is distinguished by its banded appearance, featuring layers of reddish-brown and white chalcedony. It is a more opaque gemstone compared to peridot and spinel, possessing a stone-like rather than crystal-like appearance.

A comparative overview of key properties is presented below:

Property	Peridot	Spinel	Sardonyx
Color	Yellow-Green to Brown	Varied (Red, Blue, Green, etc.)	Reddish-Brown & White Banded
Chemical Composition	Olivine (Mg,Fe)₂SiO₄	MgAl₂O₄	SiO₂ (Chalcedony)
Appearance	Crystal-like	Crystal-like	Stone-like
Transparency	Transparent	Transparent	Translucent/Opaque

Symbolism and Metaphysical Beliefs

Throughout history, each of these August birthstones has been imbued with symbolic meaning. Peridot is associated with good health, peace, and harmony, earning it the title of “gem of compassion.” It is believed to promote restful sleep and calm anger, and is even said to alleviate depression. It is also the traditional stone for celebrating a 15th wedding anniversary.

Spinel is believed to possess refreshing properties, renewing energy and fostering humility in victory. It is associated with the heart and blood-colored stones, symbolizing passion and vitality.

Sardonyx, with its historical roots, carries a legacy of strength and courage. It was historically used as a protective amulet against negative energies.

Care and Cleaning

The care required for each of these gemstones varies based on their hardness and other properties. Peridot, with a Mohs hardness of 6.5-7, requires careful handling to avoid scratches and abrasions. Cleaning can be done with warm, soapy water and a soft brush.

Spinel, with a hardness of 8, is more durable and can withstand more wear. It can be cleaned similarly to peridot.

Sardonyx, being a chalcedony, is relatively durable but can be susceptible to chipping. Gentle cleaning with warm, soapy water is recommended. Avoid harsh chemicals or ultrasonic cleaners for all three stones.

Conclusion

The August birthstones – peridot, spinel, and sardonyx – represent a fascinating blend of history, geology, and symbolism. From the ancient origins of sardonyx and the historical misidentification of spinel as ruby, to the volcanic origins of peridot and its association with Hawaiian mythology, each stone offers a unique story. The recent addition of spinel to the list of official August birthstones demonstrates a growing appreciation for the diversity and beauty of the gem world, providing those born in August with a wider range of choices to celebrate their birth month. These three gemstones, with their distinct properties and meanings, continue to captivate and inspire, embodying the warmth and vibrancy of the summer season.