Whether flashing rainbows or offering pastel calm and being a symbol of hope, opals are fascinating in so many ways. Here are my 8 reasons to treasure and admire this amazing gemstone.
1. Good for Giving
Know someone with a birthday in October? Give them some opal jewellery. Opal is the official birthstone for the tenth month of the year, and commonly associated with the Zodiac signs Scorpio and Libra. Wondering what to give that anniversary couple? If it’s their 14th wedding anniversary, then opals are the traditional choice.
2. Wet Wet Wet
On average, Opal contains 6-10% water. Yes humble rainwater, and even hot springs, play a big part in the formation of opal. It’s basically a solution of silicon dioxide and water. Where rain water falls and runs down into sandstone, it picks up silica. This silica-rich solution seeps into cracks and voids in the rock and as the water evaporates, it leaves behind a silica deposit.
3. The Science Bit
Opal is a mineraloid, rather than a mineral. Structure-wise it is what is known as amorphous. Say, what? Amorphous means it has no regular, repeating atomic structure. This is in comparison with gems like sapphire, which have a crystalline structure.
4. Precious or ‘Common’?
Opals are categorised on whether or not they exhibit a ‘play of colour’. That’s those fascinating ‘rainbow’ flashes that comes from the play of light with the water content inside the gem. If an opal displays that ‘play of colour’ it is referred to as a ‘precious opal’.
Precious opals are the ‘show offs’ of the opal world. The less showy or opaque opals, that have no ‘play of colour’, are referred to as ‘Common Opals’.
Honestly? Common opals? Now, I take exception to this ‘misnomer’! Yes, they may be more abundant than their flashy siblings but personally, I love the pearly lustre and pastel hues of these bad boys. Soft pinks, peach blushes, snow whites and ice blues. They are a great choice for some of my designs and more affordable too. The pastel shades are the result of distinctive trace elements, unique to their location of origin.
The term opalescence is commonly used to refer to the iridescence of precious opals, but gemologists define opalescence as "the pearly lustre of common opal".
See, I told you those Common Opals were not so mundane!
5. Where are they found?
Most of the world’s opal today is mined in Australia, Ethiopia, Brazil and Mexico. Most Australian deposits occur in sedimentary rocks, but opal also forms in gas cavities in volcanic rocks, as in Mexico, and Slovakia. Indeed, Slovakia was once the leading producer of fine precious opals. During the mid to late 19th century, the mines in the area of Dubnik Červenica in Slovakia were run by the Goldschmidts a family of Viennese jewellers.
6. Infamous Opals
The Harlequin Opal, 3 cm long and weighing 594 g (2,970 carats) is one of the most treasured exhibits in the Museum of Natural History in Vienna. This massive opal was mined in Slovakia in 1775.
According to legend a 700 carat black opal known as the Trojan Fire or Burning of Troy was once owned by the Empress Josephine, wife of Napoleon.
Allegedly the world's most valuable gem opal Olympic Australis was found in 1956 in Australia. Roughly 11 inches long and 4.5 inches high, it weighs 17,000 carats (3.4 kg; 7.5 lb). Amazingly it is not kept in a museum, but in the showroom of opal specialists Altman & Cherney in Sydney. Also in their showroom is the famous Aurora Australis discovered in New South Wales in 1938 and believed to be the world’s most valuable Black Opal.
7. Symbols of hope
Not surprisingly, precious opals have been treasured for centuries. Their flashes of fire were often believed to hold magical powers. Discovered in a cave in Kenya, the first known opal relics are believed to date from around 4000BC and originated in Ethiopia. According to Arabian folklore, opals fell from the heavens during lightning strikes. In Ancient Rome, opals were associated with purity and hope. The Ancient Greeks believed the gem granted the gift of perception and prophecy.
The gemstone’s name is thought to derive from the ancient Sanskrit upala, meaning “precious stone,” and later the Greek derivative “Opallios,” meaning “to see a change of colour.”
8. Definitely Lucky!
Despite historical references that suggest ancient civilisations believed opals would bring good fortune, the 19th century saw a switch in popular belief and opals were thought to be unlucky. There is some evidence to suggest that this belief was fuelled (if not started) by a novel. Published in 1829, The Maiden of the Mist or Anne of Geierstein by Sir Walter Scott, includes the story of Lady Hermione, who wore a precious opal in her hair. When a drop of holy water accidentally falls on her precious opal, its colour is destroyed and Hermione dies in a pile of ashes. Within months of the novel being published, the opal market crashed and prices were down 50%. People believed that opals were bad luck - and this reputation stuck for almost 50 years!