Black Opal in Australia – what color is black opal?
The name suggestions that black opals must be black, right? Not so!! And if it was true, they would not be very inspiring. There is nothing very special about a black gemstone. A lot of stones such as obsidian, onyx, and indeed, black potch from Lightning Ridge are either black or can be different shades of dark grey. Nothing to write home about.
The fact of the matter is that Black opals are only black in the BACKGROUND of the stone. Black opal in Australia was first discovered in the middle of the nineteenth century.
Opal cutters discovered that they could cut the color in such a way that it was presented on a background of dark grey or black, thus allowing the color to be darker, denser, and more stark, as contrasted with the paler look of white and crystal opal.
The only name they could think of at the time was ‘Black opal’ so this has stuck even though it probably gives the wrong impression when you first hear it.
A little history of black opal in Australia
Historically, opals have always been either white or milky, or slightly to fully translucent, either allowing the light to shine right through them, or if opaque (non translucent) milky in appearance. These stones are delightful natural objects with multiple colors to show but with a more delicate pale appearance.
When black opals in Australia were first discovered, the miners were at a loss to know what to call them because they had a dark appearance and a brilliance that had not been known before. It was recognized very quickly that the dense brilliant opaque colors in the foreground of the stone was because of its black background. The blacker the better. So the expression ‘black opal’ was born and has stuck for around 100 years now.
To reiterate. “black opals in Australia“ are multi-colored brilliant gems that have a denseness different to white or pale opal.
This is caused by the dark or black background of the gem consisting (in the case of “black opals in Australia” from the Lightning Ridge) of black unformed opal called ‘potch’
Black opals are also found in the Queensland opal fields in another type of stone called boulder opal, the difference being that the dark background in this case is caused by the dark brown ironstone that these gems are found in.
Australia until this time is the only country in the world where these black and boulder opals are able to be used with confidence in jewelry. Other dark opals have been found in places like Indonesia, Nevada in the USA, Africa and Tintenbar in Australia but unfortunately most of these stones are prone to cracking and some lose their color when coming in touch with water. and generally are not suitable for jewelry.
See this article in the Russian language here