![]() Black Opalĭisplaying a black body colour with little to no opalescence, this variety is now the most desirable. Most white opal comes from Marla, Australia and Whitecliffs, Australia, but is also found in Hungary, Ethiopia and Canada. However fine white opal still commands high prices and is very attractive. It is now considered to be less valuable than black opal. The best examples will show all the spectral colours. It has a white background and is sub-transparent to translucent and usually displays opalescence. This is the most ubiquitous variety of opal. Blue and green are less desirable colours, although still beautiful. Red, orange and yellow are the most desired spectral colour to be seen in opal and therefore command higher prices. Read more: How to Assess the Value of an Opalīasil Anderson sums up the identification of precious opal quite wonderfully with this quote, included in The Opal Book by Frank Leechman: "As regards to identification, there is little that need be said concerning opal, since, except in the variety of fire opal, it is a stone that cannot effectively be imitated, as soon as prismatic colours are seen."Ī cushion-cut fire opal. This cannot be confused with the reflections caused by foils within simulant opals, as play-of-colour is prismatic or rainbow-like. Diffraction of light through very small apertures between silica spheres within the structure creates these flashes of colour. This variety of opal displays play-of-colour. There are many more varieties of common opal but two other important varieties are fire opal - this is the intense orange colour opal - and hyalite, the translucent variety of opal that doesn’t display a play of colour. Read more: Questions to Ask When Buying Gemstone Jewellery Ica produces the better pinks, but both mines produce both colours. The best blues come from Caraveli and are known as Andean opal. These come from the two main provinces: Ica and Caraveli. Very pretty blues, pinks and bluish greens can be found there. Some of the more sought after common opal comes from Peru. Other names include 'landscape' opal in which the branch like structures of the iron minerals resemble that of a woodland landscape.Ĭommon green opal with dendritic inclusions, also known as moss opal. These moss like (dendritic) inclusions are formed of different iron minerals encased by the opal producing these aesthetic designs. The banded variety of common opal which can form in opalised fossils or in veins. Common opal is usually opaque to translucent and brownish orange in colour, however it can come in any colour, some of which are quite attractive. Precious opal shows a play of spectral colours though the stone whereas common opal does not. ![]() What is the difference between precious and non-precious opal? Opal can be found all over the world from Cornwall to Canada, Australia to Siberia, Ethiopia, Madagascar and many other locations.Ī cross section of opal in its host rock. It is separated into two groups, common opal (also known as potch) and precious opal (also known as noble opal). Opal is comprised of tiny silica spheres, formed when silica-rich water seeps into deep cracks and voids in the Earth’s crust. Are you fascinated by the beautiful colours of opal? Do you wish you knew more? Here, Gem-A assistant gemmology tutor, Charlie Bexfield FGA DGA EG offers a beginner's guide to opal types, including common and precious varieties.
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