What is Opal
- Opal is one of the world’s most beautiful and precious gemstones, predominantly found in Australia. It is one of only six types of precious gemstones found on planet earth, sharing prestigious company with diamonds, rubies, sapphires, emeralds, and pearls.
- Over 95% of the world’s precious opal comes from Australia, and opal is Australia’s national gemstone. In HNJF, we only use natural Australian Opal for our Fine Jewelry Items.
Different Kinds of Opal
In HNJF, we mostly use the following Opals, please kindly find out the differents.
- Also known as ‘milk’ or ‘milky’ opals, Australian white opals are distinguished by their pale white or light body tone, indicated in the below chart under “light opal”. As with any kind of opal, white opals can display any colour of the spectrum in a beautiful play of colour.
- White opals are much more plentiful and common than other kinds of opal like black opal and boulder opal. Often white opals will have white potch (colourless opal) left on the back of the stone, however sometimes the entire stone will consist of colourful opal.
- Because of their pale body tone, white opals generally have less vibrant colour than boulder opals and black opals. They do not have the advantage of having a dark or black background which enhances the stone and makes the opal colour stand out.
Doublets consist of two layers adhered together with glue:
- A black backing which is made of either black industrial glass, black potch (colourless opal), hard plastic, brown ironstone or sometimes vitrolite.
- A thin slice of opal (normally crystal opal or white opal). The thickness of the opal in a doublet can vary, however it is generally thicker than the opal found in a triplet. The edges of the slice of opal are generally rounded off (if there is enough opal) to give the stone a cabochon (domed top).
Doublets can usually be identified by looking at the side of the opal – if the stone has been adhered together you will notice that the line where the coloured opal and the black backing meet is perfectly straight. This is necessary for the two layers to be adhered together. If a doublet is set into jewellery with the sides covered, it is extremely difficult, even for an expert, to tell whether it is a doublet or a solid opal. Since the top of the stone consists of pure opal, it therefore appears exactly like a black opal, and doublets thus have a much more natural appearance than triplets.
Boulder Opal & Triples Opal
Opal was first discovered in Australia in 1872. Boulder opal is precious opal that forms in ironstone matrix, in Winton, Queensland or quartzite matrix, in Andamooka, South Australia, both locations within the Great Artesian Basin of Australia. In Winton, the opal is deposited in small veins or voids within the ironstone and is known as boulder matrix opal. If the opal forms in a banded pattern or central core the size of a walnut, it is called a Yowah nut. The boulder opal from Andamooka, is sometimes called “painted lady”. Boulder opal matrix may be brown, gray, orange or white. If the matrix is dark, the stones are known as “boulder blacks”. Opal play of color is caused by light diffraction induced by organized silica spheres within the precious opal. Boulder opal locations within the Great Artesian Basin include, Andamooka, Carbine, Jundah, Koroit, Kynuna, Mayneside, Opalton, Quilpie, Toompine and Yowah. Quilpie, Yowah and Winton are the major mining and wholesale locations with Quilpie being the largest producer. Boulder opal has also been reported from Brazil and Canada.
Triplets consist of three layers:
- A black backing as above
- A paper-thin slice of opal in the middle
A clear glass, quartz, or plastic capping in the shape of a dome. The slice of opal in a triplet is usually extremely thin (paper-thin) so the clear capping serves to give the stone a nice cabochon on top. The clear capping may also magnify the colour of the opal slightly, and also serve to protect the opal.