Red fire opal is generally more valuable than a mainly green opal which, in turn, is more valuable than a stone showing only blue colour.
Nature does not produce a red colour as often as it does a blue or green. Red colouring is caused by larger microscopic silica spheres, whereas blue is caused by the more common small spheres. Brilliance refers to the brightness and clarity of the colours displayed by opal, when the stone is viewed face-up. This ranges from brilliant , bright , to subdued or dull. The pattern of coloured segments, forming the play-of-colour of a precious opal, is unique to every individual opal.
The distinctiveness and colour displayed by these segments determines the quality of the pattern of an opal. Poor patterns are indistinct, and are characterised by patterns featuring Moss and Grass. Photos by Len Cram. The thickness of the colour bar in opal is relative to the overall size and shape of the individual stone.
Boulder opal typically has a very thin colour bar due to the way the opal is geologically formed. They are opaque and have surface blemishes. Opals are one of the most commonly worn gems; however, they are delicate and require special care.
Varying amounts of water, present in its composition, can evaporate and cause the stone to lose its gleam or even crack. Keep the following tips in mind to maintain its beauty. Keeping in mind its various characteristics will help you recognize and appreciate the value of this charming gem. Learn About Opal. Symbolism There are not many gemstones that have folklores as rich as an opal does.
Treatment Opals are generally untreated, but enhancements are often done to improve their appearance and durability. Cut Opals, unlike other gemstones such as emeralds and sapphires , are not typically faceted. Carat This gem occurs naturally in a variety of sizes, and is typically measured in carats.
Care Instructions Opals are one of the most commonly worn gems; however, they are delicate and require special care. Extreme temperatures can harm an opal.
It is essential to avoid hot or boiling water for cleaning. Also, care must be taken to keep it away from freezing cold.
A damp, soft cloth and mild cleanser can be used for cleaning. But harsh chemicals, bleach or abrasive agents must be strictly avoided as they can lead to scratches on the surface. A soft bag made of cloth can be used for storing opals so as to maintain their shine and quality.
So if you intend to store your opal jewelry for an extended period of time then seal it in a plastic bag with slightly dampened cotton wool. This is one of the ways you can help the stone retain its moisture. Consider getting your jewelry examined by professional jewelers at least once in a year. Buy Opal Rings. Oval stones generally have the best face of color and can be used in a variety of applications. Opal is almost always cut in a cabochon.
A cabochon stone is more valuable when it has a high dome compared to a a flat stone. This is due to the fact that cabochons make ideal ring stones but flat stones are less desirable because they cannot be used in many jewelry designs.
Inclusions and potch lines and are not to be confused with cracks. A crack line reflects light and greatly devalues an Opal. It is worth reading about the difference between crazing and cracking in an Opal. A potch line has no light reflection and these opals are generally valued lower but can make artistic picture patterns.
Some Opals will have a vegetation pattern from the inclusions and this is popular as the opal has replaced some of the tree or vegetation. Sand or windows also reduce the value of the opal. A window is a gap on the bottom where potch has not formed and opal is transparent.
Ethiopian opal can have a ghost or phantom inclusions or vegetation matter. These types of inclusions are generally accepted as reasonable in this type opal. The end buyer or wholesaler might not be able to consider this factor. But in the trade certain mines have a reputation of producing good quality rough that makes excellent stones. This happens in Australian and Ethiopian opal fields. Even the depth of the mine can greatly effect value.
In the trade, this can be an important factor for repeat buyers. If you find a seller has certain stocks that you like, it is best to purchase from that group. Natural Opal is always valued higher compared to treated Opal.
Over the last few years smoked or treated Ethiopian crystal opal has been sold as natural Black Opal. This treatment is not permanent. Light opal is much more desirable if it is transparent, with crystal opals with vibrant colours being particularly prized. A secondary and more complex layer of value arises when considering colours.
However, do not forget, a blue-green brilliant stone will be more valuable than a dull red. In some rare cases, the diffraction of light within an opal can cause interesting patterns to arise. These patterns can increase the value of a stone. Customers may ask why one opal costs thousands of pounds, while another is mere hundreds or less. The answer could lie in its origin. In contrast, Ethiopia is a newer source of opals, but some material has been found to have a much higher water content, making it unreliable and potentially unsuitable for jewellery.
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