Opal, the traditional birthstone of October, is a gemstone steeped in history, lore, and captivating beauty. Celebrated for its unique play-of-color, this mineraloid has been prized for centuries, embodying hope, purity, and truth. While historically linked to the zodiac signs of Libra and Scorpio, opal’s significance extends beyond astrological associations, representing a fascinating intersection of geological processes, cultural beliefs, and artistic expression. This article delves into the origins, properties, symbolism, and care of this remarkable gemstone.
History and Lore
The story of opal is interwoven with ancient myths and evolving perceptions. The origin of the name “opal” remains somewhat uncertain, with most tracing it back to the Sanskrit word upala, meaning “precious stone,” adopted into the Latin opalus around 250 BC. Some theories suggest a connection to the Ancient Greek opallios, meaning “to see a change in color,” aptly describing the gem’s most defining characteristic.
Ancient civilizations attributed various powers to opal. Ancient Greeks believed it bestowed the gift of prophecy and offered protection from disease. Europeans considered it a symbol of purity, hope, and truth, believing it embodied the virtues of all other colored gemstones. Bedouins held the belief that opal contained lightning and fell from the sky during thunderstorms. For centuries, opal was highly valued, particularly before the discovery of substantial deposits in Australia. Limited to finds in a single location in present-day Slovenia, European aristocracy considered it a rare and powerful possession, with some even claiming it could grant invisibility.
However, opal’s reputation has experienced fluctuations. A novel published in 1829, which falsely linked opal to bad luck for those not born in October, contributed to a period of superstition surrounding the stone. Despite this, its inherent beauty and unique properties have ensured its continued appeal.
Geological Formation and Sources
Opal is not a true crystal but an amorphous form of silica, chemically similar to quartz. Gem-grade opals typically contain 6% to 10% water content, a crucial component in their formation and appearance. It is a sedimentary stone, created when water rich in dissolved silicates percolates through the earth and into cavities. As the water evaporates, it deposits the silicates as microscopic spheres, gradually building up the opal structure.
While opals are found worldwide, Australia dominates the global market, producing approximately 95% of the world’s precious opals. The Australian opal fields lie in areas that were once inland seas, providing the ideal conditions for opal formation. Other sources include Brazil, Mexico, and the western United States, though these deposits yield a smaller proportion of the world’s supply.
Gemological Properties
Opal’s defining characteristic is its “play-of-color,” a mesmerizing display of shifting rainbow hues. This phenomenon occurs when light enters the microscopic silica spheres within the opal, diffracting and creating a spectrum of colors. The quality and intensity of the play-of-color are key factors in determining an opal’s value.
Opal ranges from 5 to 6.5 on the Mohs scale of hardness, making it relatively softer than many other gemstones. This means it is susceptible to scratches and requires careful handling. Prolonged exposure to water can weaken the adhesive in opal doublets and triplets, and sudden temperature changes or high heat can cause fracturing, even in natural opal.
Opals are categorized into two main varieties: precious and common. Precious opals exhibit the play-of-color, while common opals do not. Within precious opals, further classifications exist based on body tone and color patterns. Black opals, with dark body tones, are considered the most valuable, as they provide a striking contrast that enhances the play-of-color. White opals, with lighter body tones, are more affordable and often used in larger pieces of jewelry.
| Property | Description |
|---|---|
| Chemical Formula | Hydrated amorphous silica (SiO₂·nH₂O) |
| Hardness (Mohs) | 5 - 6.5 |
| Specific Gravity | 1.98 - 2.15 |
| Luster | Vitreous to resinous |
| Transparency | Translucent to opaque |
| Play-of-Color | Present in precious opals |
Symbolism and Metaphysical Beliefs
Throughout history, opal has been imbued with symbolic meaning. Traditionally, it is associated with loyalty, faithfulness, purity, hope, and confidence. It is believed to enhance vision, both physically and intuitively, fostering imagination and dreams.
Modern metaphysical beliefs attribute additional properties to opal. It is considered an emotional amplifier, magnifying feelings and facilitating healing. Artists are said to wear opal to unlock creativity and spontaneous insight. Its hydrous makeup links it to the element of water, enhancing intuition and promoting fluid change.
Care and Cleaning
Due to its relative softness and porous nature, opal requires special care. The safest way to clean opal is with warm, soapy water and a soft cloth. Avoid harsh chemicals, ultrasonic cleaners, and abrasive materials, as these can damage the stone or its delicate structure. Opal doublets and triplets, which consist of a thin slice of opal glued to a base material and covered with a quartz dome, are particularly vulnerable to damage from harsh cleaning methods.
It is recommended to store opal jewelry separately from harder gemstones, such as diamonds, rubies, and sapphires, to prevent scratching. Additionally, protect opal from prolonged exposure to heat or direct sunlight, as this can cause dehydration and cracking.
Alternatives to Opal
While opal remains the traditional October birthstone, pink tourmaline and rose quartz are recognized alternatives. Pink tourmaline, adopted in 1912 by the National Association of Jewelers, symbolizes friendship, compassion, and balance. Rose quartz, linked to the zodiac sign Scorpio, is associated with love, self-love, and forgiveness.
Buying Opal
When purchasing opal, several factors should be considered. The play-of-color is paramount, with brighter, multi-hued flashes indicating higher value. The body tone also plays a role, with black and dark-gray opals commanding premium prices due to their contrasting backgrounds. Inspect the stone under magnification for cracks or crazing, which can spread over time. A healthy opal should feel cool and “waxy” to the touch, not brittle or chalky. It is also important to inquire about any treatments the stone may have undergone, such as smoking, sugaring, or resin impregnation, as natural stones generally hold better resale value. The cut style should also be considered, with high domes intensifying color but sitting higher in settings, while low domes are more suitable for rings worn daily.
Conclusion
Opal, the captivating birthstone of October, continues to enchant with its ethereal beauty and rich history. From ancient beliefs in its prophetic powers to modern metaphysical interpretations of its emotional healing properties, this gemstone has held a special place in human culture for centuries. Its unique play-of-color, geological origins, and delicate nature make it a truly remarkable and cherished gem. Whether admired for its aesthetic appeal or valued for its symbolic significance, opal remains a timeless treasure, embodying hope, purity, and the enduring allure of the natural world.