The beautiful gem Opal has been one of the strongest jewellery trends over the past decade. The gemstone came into spotlight when Cartier used it prominently in its famed 2008 “Chimera collection” at the Biennale des Antiquaries in Paris.
Today, this stone is an integral part of most jewellery houses, its mystery and vivacity in perfect sync with the rising interest in spirituality and awareness of the environment.
Where Are They Found?
The best Opals are mainly found in sedimentary rock deposits in places like Queensland and New South Wales in Australia, which accounts for roughly 95% of the global production. Opals are also found in countries like USA, Mexico, Brazil, Canada and Slovakia, among others.
Types & Colours:
The two primary varieties of this gemstone are precious opal and common opal. A precious opal is known by its characteristic play of colours and is quite rare. Common opals also called “potch”, do no exhibit this trait and are found in abundance across the world.
Interestingly almost 90-95% of opals are of the common, single-coloured variety (white, grey & black), while approximately 5% have ‘some’ colour. Less than 1% of opals have real “value”.
What makes the opal truly unique is its ability to display all the colours of the spectrum depending on the angle it is held. This ‘play of colours’ is caused by the interference and diffraction of light when it passes through the small silica spheres that make up its interiors.
How are Opals Formed?
Opals are basically a combination of water and silicon dioxide. Water flowing through cracks in sandstone picks up tiny particles of silica. Over a long period of time, this solution solidifies into a hard gel like substance to form opals. Opals have also been found in fossilized shell, wood and bone.
An opal therefore cannot be called a crystal, but rather an amorphous solid. According to experts this was also the process that preceded the formation of opals in volcanic areas of inland Australia about 70 million of years ago.
The secret behind their ‘Colour’:
Only the best quality opals have the ability to refract colours. This is due to the diffraction of white light by its silica spheres and voids which then dissipates it into a rainbow of colours. Again it’s the size and space between such spheres that decides the colour of the opal itself.
The more commonly found blue opals are the result of smaller spheres, while the extremely rare red variety is formed by much larger spheres. One of rarest opals in the world (Harlequin Opal) is known for its ability to display colour patterns akin to a checkerboard.
Are Opals Unlucky?
Many people do seem to think so, but this belief is more the result of a silly myth, than any real evidence. And the (mis) credit for this goes to Sir Walter Scott’s bestselling 1829 novel, Anne of Geuerstein.
The novel tells the story of Lady Hermione, who is falsely accused of being a demoness, and dies shortly after a drop of holy water accidentally falls on her opal and destroys its color.
It was just a piece of fiction that readers misinterpreted as the truth. Within months of its publication, the opal market crashed and prices were down 50%. But mercifully the market revived yet again nearly half a decade later with the chance discovery of an amazing black opal in New South Wales (Australia) in 1877.
Myths & Legends:
Opals have a very long history and there are many myths pertaining to the stone. In ancient times, opals were a symbol of fidelity and later a tool for emotional prayer. Opals are also believed to have curative properties for vision-related problems.
Others believed that when worn as an amulet they had the power to make the wearer immune to any disease and enhanced his mental faculties. The opal is also a symbol of justice and peace and is used as divine protection in dangerous places.
Expert Tip: Opals contain between 5-20% water which tends to dry out eventually making the stones soften and prone to cracks. Interestingly enough, it’s these very cracks and imperfections that are also responsible for one of its biggest attributes – their colour or fire. Opals with cracks that are visible to the naked eye are considered to be of an inferior quality.