Opal, alongside tourmaline, holds the distinction of being a birthstone for those born in October. Revered for millennia for its captivating play-of-color and rich history, opal is a gemstone unlike any other. From ancient beliefs attributing supernatural powers to its shimmering depths to its modern appreciation for its unique beauty, opal continues to fascinate and inspire. This article will delve into the history, geological origins, gemological properties, symbolism, and care of this remarkable gemstone.
History and Lore
The story of opal is interwoven with tales of ancient civilizations and evolving beliefs. The name “opal” is believed to originate from the Greek word “Opallos,” signifying a shift in color, a fitting descriptor for this dynamic gem. Some theories suggest a Sanskrit root, “upala,” meaning “precious stone,” further highlighting its historical value. Ancient Romans considered opal a symbol of hope and love, referring to it as opalus, a “precious stone.”
Throughout history, diverse cultures have imbued opal with unique significance. Ancient Greeks believed the gemstone bestowed the gift of prophecy and offered protection from disease. In contrast, Bedouins held the belief that opals contained lightning and were fragments fallen from the sky during thunderstorms. European traditions long considered opal a symbol of purity, hope, and truth, and for centuries, it was thought to embody the virtues of all colored stones. During the Middle Ages, opal was associated with good luck, while in Victorian times, Queen Victoria was a noted collector and admirer of the gem.
Geological Formation and Sources
Opal is unique in that it is not a crystalline gemstone like diamonds or rubies, but rather a mineraloid – an amorphous form of hydrated silica. It forms through the gradual natural heating of silica gel found in the cracks and crevices of rocks. Seasonal rains play a crucial role in this process, as water carrying dissolved silica percolates into the ground. As the water evaporates, these silica deposits are left behind, slowly building up to form opal.
While opal was historically sourced from India, the most significant and abundant sources today are found in Australia. Commercial mining in Australia began in the 1890s, quickly establishing the country as the world’s primary supplier of this October birthstone. However, opal is also found in other locations around the globe, including Ethiopia, Mexico, Brazil, the United States, Central Europe, Honduras, Indonesia, Madagascar, Peru, and Turkey. Each geographical location contributes to the distinctive character and hues of the opal found there.
Gemological Properties
The most defining characteristic of opal is its “play-of-color” – the shifting rainbow hues that dance within the stone. This phenomenon is caused by the diffraction of light as it passes through microscopic spheres of silica within the opal. The size and arrangement of these spheres determine the colors displayed.
Opals are generally classified into two broad categories: precious and common. Precious opal exhibits this play-of-color, while common opal does not. The value of an opal is determined by several factors, including the brilliance and variety of its play-of-color, its clarity, cut, and carat weight.
Opal ranks between 5.5 and 6.5 on the Mohs scale of hardness, making it softer than many other gemstones. This relative softness requires careful handling and consideration when designing and wearing opal jewelry.
Symbolism and Metaphysical Beliefs
Throughout history, opal has been associated with a wide range of symbolic meanings and metaphysical beliefs. It has been credited with numerous supernatural origins and powers, and was believed to inspire confidence and hope in the wearer. Ancient cultures believed opal could bestow prophetic abilities and offer protection from illness. The gem’s varied colors have also led to associations with different emotions and energies.
In modern times, opal is often associated with creativity, inspiration, and emotional healing. Some believe it can amplify emotions and encourage individuality. It is also the traditional gemstone given to celebrate the 14th wedding anniversary, symbolizing fidelity and enduring love.
Care and Cleaning
Due to its relatively low hardness, opal requires special care to maintain its beauty. It is susceptible to scratching and should be protected from impacts. Avoid exposing opal to harsh chemicals, extreme temperatures, or ultrasonic cleaners.
Cleaning opal jewelry can be done gently with a soft cloth and lukewarm soapy water. Avoid abrasive cleaners or brushes, as these can damage the surface of the stone. It is also important to store opal jewelry separately from other gemstones to prevent scratching. Opals can sometimes lose water content over time, leading to cracking. To prevent this, it is recommended to occasionally immerse the opal in water for a short period.
Conclusion
Opal remains a captivating and historically significant gemstone. From its ancient origins and diverse cultural interpretations to its unique play-of-color and relative softness, opal offers a fascinating study in gemology and human fascination. As a traditional and cherished birthstone for October, opal continues to symbolize hope, purity, and the beauty of individuality. Its enduring appeal ensures its place as a treasured gemstone for generations to come.