Find out all about opals - an iconic australian gemstone
The following information gives a brief rundown on the three main types of opals that are available and the three main techniques used when displaying them in jewellery. Opals have become an iconic part of the Australian souvenir market with tourists wanting to take home a unique piece of Australia.
Black Opal
Black Opal is characterised by a dark body tone causing brightness of colour which is unmatched by lighter opals. Black Opals are usually mined in Lightning Ridge, New South Wales, and are the most famous, and sought-after type of opal. The term 'black opal' does not mean that the stone is completely black (a common mistake), it simply means the stone has a dark body tone in comparison to a white opal.
White Opal
Also known as 'milky opal', white opal features light white body tones, and is mined in South Australia. White opal is more common and because of its body tone, generally does not show the colour as well as black opal. Nevertheless, white opals can still be absolutely magnificent in colour if a good quality stone is found.
Boulder Opal
Boulder opal forms on ironstone boulders in Queensland. This type of opal is often cut with the ironstone left on the back, as the opal seam is usually quite thin. Leaving the ironstone on the back means that boulder opal can be very dark and beautiful in colour. The opal forms within the cavities of the boulders in both vertical and horizontal cracks. Boulders vary in shape and size, from as small as a pea, to as big as a family car. Boulder Opal has a tendency to cleave; when cleaved the "split" leaves two faces of opal, with a naturally polished face.
There are three main techniques used for setting opals; solid, doublet and triplet. As the name suggests, a solid opal is exactly that - a solid piece of opal in it's natural state that has been shaped and polished. Doublets and triplets consist of a paper-thin slice of opal cemented to a black backing. Triplets have, in addition to this, a clear quartz or glass capping over the top to magnify the colour, protect the stone, and give it a cabochon (domed) appearance. The idea of doublets and triplets is to imitate valuable black opals at a fraction of the cost. The following diagrams show the differences between solid, doublet and triplet opals.
Solid Opal
Most cutters prefer to produce the opal as a solid cut 'en cabochon' if the gem is sufficiently thick. The opal is left in its natural state and simply shaped and polished on the cutter's wheel.
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Doublet Opal
A thin veneer of opal may show enhanced colour with a dark backing of either black or grey silica material, or a thin slice of common opal cemented to the back of the opal with epoxy resin.
Solid Opal
Most cutters prefer to produce the opal as a solid cut 'en cabochon' if the gem is sufficiently thick. The opal is left in its natural state and simply shaped and polished on the cutter's wheel.
You can find a great range of Opal Jewellery on our website or come and see our collection in store.
Ground Floor - Canberra Centre - Canberra
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