There are many types of rough opal from many parts of the world. Rough opal comes in many forms, shapes and sizes. In Ethiopia, opal comes in a nobby-like form that is usually brownish in tint. The opal looks very volcanic and porous, so water or liquids will soak into the opal easily. This type of opal tends to crack or craze over time of being out of the ground and not under pressure.
Brazilian opal comes in the form of seam opal that forms in fissures and cavities in the high silica concentrated ground.
This opal is usually crystal opal and is mainly stable and not conducive to cracking or crazing. The opal is considered a precious opal.
Out of all the opal in the world, there is no better and more valuable type of opal than Lightning Ridge opal rough. When you hit a patch of opal black opal, you know it because you know you’re on the money and your life is about to change financially.
Black opal is mainly only found in Lightning Ridge and supplies 98 per cent of the world’s supply. A small opal mining field in Coober Pedy also has produced black opal, but not in the quantities of the Coocoran and Grawin opal fields in Lightning Ridge.
The type of opal you can get from Lightning Ridge can be a mixture of seam and nobby opal and can be crystal, black, and white opal. Black opal is the most valuable followed by crystal opal and at the end, white opal. All of which can be found in the same patch of opal bearing ground. Most people are searching for the elusive black opal.
Cutting black opal rough is the most challenging type of opal to cut in the world, and experience is a must. It takes many years of knowledge to understand how and what is the best way to cut rough black opal. Experience only found through time and an understanding of each different opal field in Lightning Ridge.
Rough opal has become more and more popular around the world as the online world make it easier for people to buy without going to the opal fields and spending thousands of dollars to travel there.