Opal, the traditional and original birthstone of October, is celebrated for its captivating “play-of-color”—a mesmerizing display of shifting rainbow hues. Alongside tourmaline, it represents the vibrant and diverse palette of autumn, offering a unique and enchanting gemstone for those born in the tenth month. Revered throughout history for its beauty and believed powers, opal continues to be a prized gem in modern jewelry, admired for its ethereal appeal and distinctive character.
History and Lore
The story of opal stretches back to ancient times, with origins in India where it was known as ‘upala,’ meaning precious stone. This evolved into ‘opalus’ in ancient Rome, where the gem was highly valued. Ancient Greeks believed opals bestowed the gift of prophecy and offered protection from disease. Europeans long considered opal a symbol of purity, hope, and truth. Bedouin tribes held the belief that opal contained lightning and descended from the sky during thunderstorms.
For centuries, opal has been associated with luck and inspiration. Its listing as the official October birthstone by the American National Retail Jeweler’s Association in 1912 solidified its place in modern birthstone tradition, though its historical significance predates this recognition by millennia. Opal is also the traditional gemstone given to celebrate the 14th wedding anniversary.
Geological Formation and Sources
Opal’s formation is a unique geological process. The gem is composed of hydrated amorphous silica, meaning it’s not a crystalline structure like many other gemstones. The “play-of-color” arises from the diffraction of light as it passes through microscopic silica spheres within the opal.
Australia currently dominates the global opal market, producing over 90% of the world’s supply. However, significant deposits are also found in Ethiopia, Mexico, and Brazil. Within the United States, opal can be found in Nevada (particularly Virgin Valley, known for black opal), Oregon (Opal Butte and surrounding areas), and Idaho (Spencer Opal Mines). Central Europe, Honduras, Indonesia, Madagascar, Peru, and Turkey also yield opal, each location contributing to the gem’s distinctive character and hues.
Gemological Properties
The defining characteristic of opal is its play-of-color, the shifting display of rainbow hues that dance across its surface. This phenomenon, known as ‘opalescence,’ is what sets opal apart from other gemstones. While the base color of opal can range from white to black, it is the interplay of colors that truly defines its beauty.
Opal’s hardness ranges from 5.5 to 6.5 on the Mohs scale, making it a relatively soft gemstone and requiring careful handling. Its composition is hydrated amorphous silica, with a variable water content that can affect its stability.
Several types of opal are recognized, including:
- White or Milky Opal: The most common type, characterized by a white or pale base color.
- Black Opal: A rare and highly prized variety with a dark body tone, which intensifies the play-of-color.
- Fire Opal: Transparent opal displaying warm oranges and reds.
- Boulder Opal: Found within ironstone rock, often exhibiting striking patterns and colors.
Modern Uses and Jewelry Styles
Opal’s captivating play of colors makes it a popular choice in modern jewelry. It is frequently set in gold or silver and used in a variety of designs, including:
- Rings: Opal rings, including engagement rings, are gaining popularity for their unique and vibrant appearance.
- Necklaces and Pendants: Pendants and necklaces showcase the beauty of opal, often cut en cabochon to highlight its colors.
- Earrings: Opal earrings range from elegant studs to dangling designs, often paired with diamonds or other gemstones.
- Brooches: Both vintage and modern brooches feature opal, creating stunning decorative pieces.
- Bracelets and Bangles: Opal adds a touch of elegant color to wristwear.
- Art and Sculpture: Opal is also used in art and sculpture, showcasing its unique beauty.
One notable example is the Andamooka Opal, presented to Queen Elizabeth II in 1954, a large oval-shaped opal displaying an impressive array of colors.
Care and Cleaning
Due to its relatively soft nature, opal requires careful handling and maintenance. It is susceptible to scratching and can be damaged by harsh chemicals or extreme temperatures. To care for opal jewelry:
- Avoid exposure to harsh chemicals, such as cleaning agents or cosmetics.
- Clean with a soft cloth and lukewarm water.
- Avoid ultrasonic cleaners or steam cleaning.
- Store opal jewelry separately from other gemstones to prevent scratching.
- Protect opal from impacts and extreme temperature changes, as these can cause cracking or crazing.
Symbolism and Metaphysical Beliefs
Throughout history, opal has been imbued with various symbolic meanings. It has been associated with hope, inspiration, creativity, and purity. Ancient cultures believed opal possessed protective qualities and the ability to bestow prophetic gifts. While modern gemology focuses on the scientific properties of gemstones, the enduring symbolism of opal continues to resonate with many.
Conclusion
Opal, the mesmerizing birthstone of October, stands as a testament to the beauty and wonder of the natural world. From its ancient origins and rich history to its unique geological formation and captivating play-of-color, opal continues to enchant and inspire. Whether admired for its aesthetic appeal or cherished for its symbolic significance, opal remains a treasured gemstone for generations to come. Its delicate beauty requires careful handling, but the reward is a gemstone that truly captures the essence of color and light.