At The Good Opal co. quality matters.
At the Good Opal co, we stock black opal from both the now closed town of Mintabie (closed in 2019) and the renowned town of Lightning Ridge because we celebrate all Australian opal and recognise its unique qualities and differences in colour, pattern, formation; the list goes on.
Black opal is the rarest and most valuable gem in the world. Top of the range gem quality black opal can be worth up to AUD $40,000 per gram. However, just because an opal is black, that doesn’t make it valuable. There are many factors including brightness, presence of colour and pattern, which determine the overall value of opal. As seen in the image to the right, whilst stunning, none of these opals are perfect, they have potch in the face, some aren’t quite as bright as others or bare the stunning red fire that is highly prized by the global market. But these imperfections are what make beautiful opals like these affordable.
A little bit of history…
Black opal bares its name due to the dark body tone of the opal– the colour of the opal when you turn it over. The darker the body the more valuable the stone may be. It is this darkness that lends brightness to the other colours displayed with in the gemstone. Whilst dark opal has been found in other areas including white cliffs and Coober Pedy, Black opal can now only be found on one place on earth and that is in the small town of Lightning Ridge NSW. Lightning Ridge is the black opal capital of the world, producing 95% of the world’s Black Opal.
Unlike other variations of opal, black opals have carbon and iron oxide trace elements present, which cause the unusual darkness of the stone. Because of their dark body tone, the rainbow colours in a black opal stand out much better than lighter opals making them the rarest and most highly prized opal with a value vastly higher then other opal types.
Formation
Of all gemstones, when opal was formed through cervices in the earth filled with silica rich water 100 million years ago, silica deposits were left behind. These deposits were spherical in nature, and it is their stacking— layer upon layer—that creates gaps between the spheres. When the light passes through the spheres and their gaps, it splits like a rainbow from a prism. The result is the stunning patterns and displays of colour we see in black opal.
The vibrancy of colour in Black opal makes it the most valuable form of all opals. Often a black opal will have a natural layer of potch (colourless opal) left on the back of the stone, which can give the stone an extra darkness and vibrancy of colour. The darker this potch backing is, the darker the body tone, which usually makes for greater vibrancy of colour and a higher value black opal.
This is the principle behind the creation of doublets and triplets which are crystal or milky opals, placed on a dark background to provide the best display of colours that the opal bears. This is also why Boulder opal is so vibrant, the natural darkness of the iron stone present in boulder opal makes for intense and vibrant displays of colour and this is why clean boulder opal (no iron stone present in the face-very rare) is the second most highly priced Australian Opal.
Areas where black opal has been found: Mintabie (now closed), White cliffs, Lightning Ridge*
Shop our full Opal Range at https://www.goodopalco.com/product-category/opals/black-opals/
