There are many different Opal types available and many opal features that determine the valuation of an opal.
Solid opal is a natural opal type and is cut, shaped and polished from a single piece of opal.
It has colour in its facing with a natural coloured backing. The darker the backing, the stronger the opal face colours will appear to be, reflecting out color more effectively than a lighter backing.
An opal doublet is a piece of solid precious colored opal (transparent or translucent) glued to a dark backing, usually of black potch. This dark base not only enhances the opal's colours but gives added strength and thickness to the opal piece.
Therefore a doublet opal type is ideal when a natural opal is beautiful in its colors
(e.g. a crystal opal) but is either too thin to be made into a single
opal stone or the opal has no natural dark base backing to reflect its
Giving it a dark base backing, whether black potch, boulder, glass, obsidian, black jade etc. allows the opal's colors to shine out.
Therefore a doublet opal type is made up from natural opaland a dark base backing.
A triplet opal type comprises three parts; a dark-base backing, a glass cap & a thin slice of coloured opal glued between the backing and glass cap. The triplet utilises only a thin slice of opal so the glass cap protects the layer of opal.
(Opal Types - Basically Solid = 1 layer, Doublet = 2 layers, Triplet = 3 layers )
Small pieces of opal chips are glued to a dark backing and enclosed in resin, sometimes giving resemblance of a solid opal, but it is more normally used in
jewelry making (watch faces) etc..
However, truly stunning mosaics are created when larger slices of gem grade opal are utilised and planned out in specific patterns, with the opal sides fitting perfectly against each other - like in the photograph of this Mosaic Opal Pendant, which I created many years ago.
* A point of note... with my own mosaic creations, I only use genuine natural quality quartz crystal when cutting a cap for them.
"Picture" mosaics that illustrate a landscape/portrait etc. are the most valuable of all !
We have kindly been given permission
to show this beautiful and mystical Opal Mosaic as an example of a "picture" mosaic....
It is in fact one of the most stunning that we have ever seen and we have been told that it took over five years to produce!
(* Picture Copyright)
The creator of this gorgeous opal mosaic resides in Cooberpedy.... one of our Australian Opal mining towns.
Opal inlay is comprised of small pieces of crystal opal that are inlaid straight into jewellery channels
or inlaying fine Crystal Opal into a host medium, such as other opal, boulder opal and other compatible semi-precious stones.
Boulder & Matrix Opal
Boulder Opal is a thin layer of opal that is naturally attached to it's brown ironstone host rock.
Matrix Opal is where the precious opal infuses &
permeate into sandstone and ironstone, filling the crevices and holes of it's host rock.
Another form of opal is the Yowah Nut.
This is rare and looks like an oval nut of about 5 cm across and is an ironstone formation.
The nut has to be split open to reveal the mirror opal images that are produced inside it. The opal either forms as a solid kernel (very rare) or as concentric infused layers of opal within the host rock.
The Color of Opal .....
Opals are usually cut and polished in round or oval cabachons, depending on the raw material. This brings out the best play of colour of the opal.
A mixed range of colours of red, blue green are the most valuable,particularly if they are very bright or fiery which is a major consideration of value.
Pattern of colour is also important.
If the colour red appears when looking at an opal, then the opal will contain all other colours also.
The evaluation of an opal is determined by it's play of colour, it's patterning, its thickness, it's cut, weight and finish.
Crystal opal is more transparent with a deep play of colours and second to the black opal.
White/Milky opals show more lighter (diffused) colour and are the least expensive of the opal range.
Black Opal ......
Black opal or opal with dark base show more of the brilliant play of colours of an opal.
A Black opal (top quality of course from Lightning Ridge!) is a natural solid opal stone with a black or nearly black body tone (background).
By closing one's eyes and squinting at the face of the stone all other colours are ignored and the "body tone" (darkness level of the opal) can be seen more clearly, showing the depth of the "blackness" of the stone.
The term Black Opal is somewhat misleading as the opal is not 'black' in colour, but has a very dark base body colour, which enhances the brilliance of the diffracted colours.
An opal is considered a Black Opal only when it is in the depths of N1 to N4, then escalating down to Dark and Light opals.
Black Opal...N1 to N4..........Dark Opal N5-6........Light Opal N7-N9....
Investing In Opal .....
The following points should be considered when purchasing or investing in opal.
You Looking For More Opal
those of you who are interested in reading up on more in-depth
information about Opals
- we have only given you the simplest descriptions - then take a
look at our Opal Information section in
Links of Interest.
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