Opals, with their mesmerizing play of colours and historical allure, have captivated humanity for centuries. These gemstones, formed from silicon dioxide and water, take millions of years to develop. They are a true testament to nature's artistry and patience. In this blog we explore their origins, types, and the myths surrounding them, as well as practical tips for their care and contemporary appeal.
What is an Opal?
Opal is a hydrated amorphous form of silica (SiO2·nH2O). Unlike other gemstones, opals do not have a crystalline structure; instead, they consist of microscopic silica spheres arranged in a grid-like pattern. This unique structure results in the opal's characteristic "play-of-colour," a dazzling display of rainbow colours that change with the angle of light. It takes millions of years for opals to form, often in the fissures of almost any kind of rock, most commonly limonite, sandstone, rhyolite, and basalt.
Main World Localities
Opals are primarily mined in Australia, which produces about 95% of the world's precious opals. Other notable sources include Ethiopia, Mexico, Brazil, and the United States. Each locality is known for producing opals with distinct characteristics:
Australia: Famous for its black opals from Lightning Ridge, white opals from Coober Pedy, and boulder opals from Queensland.
Ethiopia: Known for its vibrant and diverse opals, including the unique Welo opals.
Mexico: Renowned for its fire opals, which often display a warm, fiery colour without the play-of-colour.
Precious vs. Non-Precious Opal
Opals can be categorized into two main types: precious and common (or non-precious).
Precious Opal: These opals exhibit a play-of-colour, which means they display a range of colours as they are rotated in light. Examples include black opals, white opals, and boulder opals.
Common Opal: These opals, also known as "potch," lack the play-of-colour and are typically opaque with a more uniform colour.
Black Opal vs. White Opal
The primary difference between black and white opal lies in their background colour and vibrancy:
Black Opal: These have a dark body tone, which makes the play-of-colour more vibrant and striking. They are among the most valued opals and are primarily found in Lightning Ridge, Australia.
White Opal: These have a light or white body tone and generally display a more subtle play-of-colour. They are more common and are primarily sourced from Coober Pedy, Australia.
Opals displaying reds and purples are the most prized and valuable because these are the rarer colours.
Crystal and Fire Opal
Crystal Opal: A type of precious opal with a transparent or semi-transparent body that can display a brilliant play-of-colour.
Fire Opal: Usually found in Mexico, these opals are known for their vivid, warm body colours ranging from yellow to orange to red. They may or may not display a play-of-colour.
The Lore and Myths of Opals
Opals have a fascinating and complex history filled with myths and legends. According to Arab tradition, opals were created by lightning strikes, trapping flashes of lightning within the stone.
The first recorded mention of opals dates back to Ancient Greece, where Plato's “Republic” describes an invisibility stone, which later retellings identified as opal. In the Middle Ages, opals were known as the "magician's stone" because their varied colours were believed to hold the powers of all gemstones.
However, the opal's reputation changed over time. In 1829, Sir Walter Scott's novel "Anne of Geierstein" contributed to the superstition that opals bring bad luck. In the story, Lady Hermione wears an opal that loses its lustre and leads to her apparent demise when touched by holy water. Although the novel reveals that Hermione's death was caused by poison, many readers did not reach this conclusion due to the novel's serialized publication.
Queen Victoria, an opal enthusiast, tried to revive the stone's popularity. Unfortunately, at her coronation, her opal brooch failed, reinforcing the gem's unlucky reputation.
In the late 19th century, a series of unfortunate events further tarnished the opal's image. King Alfonso XII of Spain gifted an opal ring to his wife, Princess Mercedes, who died mysteriously soon after. The ring then passed to other family members, each of whom also died shortly after receiving it, including the king himself. These deaths were likely due to a cholera epidemic rather than the opal, but the stone was blamed for the misfortunes.
Despite its tumultuous history, the negative perception of opals is largely unfounded. Today, opals are cherished for their beauty and uniqueness, dispelling the myths of bad luck associated with them.
Preventing and Treating Opal Cracking
Opals are sensitive to changes in temperature and humidity. They can sometimes crack if left in dry conditions for extended periods, such as being stored in jewellers paper packets. This phenomenon, known as "crazing," occurs because opals contain water that can evaporate, causing the stone to shrink and crack. This could be why in the past opals have been associated with bad luck. However in reality opal crazing is a relatively rare occurrence.
While it is not possible to reverse the cracking once it occurs, treatments such as Opticon resin can help prevent further damage and disguise the cracks. Opticon is a professional treatment that can save the opals but whether the cost of treatment is worth it will need to be carefully considered. Opticon has also traditionally been used to stabilise emeralds which often have naturally occurring fractures in them.
If you are lucky enough to own opals you should wear them regularly so that they can absorb the moisture that they need. Avoid storing them for long periods in very dry environments. If you need to clean them a slightly damp cloth can be used or take them to a jeweller who can clean them professionally for you. This applies to all jewellery, not just opals, jewellers know how to clean gemstones and will always be able to make them look sparkling and new, this is very difficult to achieve at home unless you know what you are doing and have the right equipment.
Modern Appeal of Opals
Opals were once considered the choice of older ladies, often fashioned in oval shapes with diamond surrounds. However, with the rise in popularity of TV shows like "Outback Opal Hunters," the discovery of Ethiopian opals, and the industry's embrace of innovative styles, opals have regained popularity across all age groups and customer types. Contemporary designs now showcase opals in various styles, shapes, and settings, making them a versatile choice for modern jewellery. Check out Cheal Opals here.
Conclusion
Opals are a treasure of the natural world, with their vibrant colours and unique patterns captivating collectors and jewellery enthusiasts alike. By understanding their characteristics, dispelling myths, and taking proper care, you can enjoy the beauty and elegance of opals for a lifetime. Explore the diverse styles and designs available today and find the perfect opal piece to suit your taste and style. Wear your opals proudly, knowing they are a timeless and beautiful gemstone.
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