The Opal Mine: Study Area

The Study Area

Besides being the home of manufacturing and selling opal jewellery, The Opal Mine is also a place where you can really learn more about opals. For the best selection of stones and styles, you must go to the specialists.

If you want to avoid buying synthetics, doublet, triplets, dyed, inferior or over-valued opals, visit the Study Area inside The Opal Mine and teach yourself how to distinguish genuine opal from its treated and synthetic counterparts.

Black Opal - is precious opal showing a play of spectral colours in a dark colour which is usually black, blue, brown or grey (semi-black opal). Black opal is highly-priced because it is rare and the colour are bright with strong fire.

Boulder opal - is a variety of precious opal, usually crystal opal found as veins or cavity fillings in a dark iron-stained sandstone or mudstone.

Crystal opal - has a body colour ranging from almost clear to milky white. Clear varieties are known as crystal opal depending on the degree of clarity. Crystal opal is the most common gem found in South Australian opal fields.

Doublets are usually two pieces of opal cemented together using a thin high grade light opal on a black potch or glass back.

Triplets are doublets with clear domed caps of glass or quartz cemented to the face, protecting the opal and amgnifying the pattern, They always have a natural backing of black potch.

Treated opal - Andamooka matrix comprised precious opaline silica as an infilling of the pore spaces in silty claystone; it generally shows fine pinfire colour in the natural state. The colour may be enhance by soaking the specimen in a sugar solution and then boiling in acid to deposit carbon in the available pore spaces, resulting in a dark background. Matrix opal is generally cut and sold as solids.

Synthetic opal - Synthetic opal, such as Gilson, is opaline silica produced in the laboratory and having a similar structure to that of precious opal. As detection of synthetic opal is relatively difficult, it is highly recommended to buy genuine opal from reputable cutters.


Besides being the home of manufacturing and selling opal jewellery, The Opal Mine is also a place where you can really learn more about opals. For the best selection of stones and styles, you must go to the specialists.		If you want to avoid buying synthetics, doublet, triplets, dyed, inferior or over-valued opals, visit the Study Area inside The Opal Mine and teach yourself how to distinguish genuine opal from its treated and synthetic counterparts.