the hunt for black opal – Lightning ridge Australia
Black opal is the most valuable of the opals and exhibits the strongest display of colors. It can be found in various locations around the globe, such as Ethiopia and Honduras. However, by far the best quality of black opal has been found in Australia. Located ~480 miles (~770km) northwest of Sydney, a small town is the home of one of the most coveted gemstones of this planet. “Lightning Ridge has only 3000 souls. They tried to get down an exact number once, but due to the remote living conditions and people traveling in and out of this region, this is nothing but a rough estimate,” explains Alexander Kreis.
ONLY 0.25% IS OF HIGH LUXURY QUALIty
Situated between fossils of the Cretaceous era, black opal is mined in a depth of 20ft. – 59ft. (6m – 18m). Set in Sandstone sediment, miners can excavate these treasures with picks and self-made machinery. However, the sporadic distribution in the ground makes it hard to find. The underlying process is one of trial and error.
“Miners usually do test drills. They first mine a shaft into the ground and see if they find traces of opal. Then, should they find some, they follow these fractures and faults to find opal,” explains Alexander Kreis, a gemologist at Kreis. The sporadic nature of opals’ occurrence causes some miners to have no valuable production for years. “I guess every miner in Lightning Ridge knows of some stories of people who became rich overnight by finding a large pocket of opals, as well as some stories of miners who have been mining for a decade without having any significant production,” tells Stefan Kreis.
Around 95% of all opals mined is called “potch”, which is of no value. “Potch” has no noteworthy display of color and is usually gray, white, or black. Of the remaining 5% are again ~95% of mediocre quality. Only 0.25% of the whole production does exhibit a very strong color in combination with a wide range. Colors such as a deep blue and a green reminiscent of the Great Barrier Reef.
water, an essential ingredient
“finding a water source is a problem to many”
Essential for the mining process is the separation of “potch” and dirt from the more valuable black opals. Used for this step is an agitator. With the help of water, the material is constantly moved around within the machine, washing out the dirt. What remains is “potch”, grovel and the high-quality black opals. This process takes up to a week and the essential ingredient is water.
“Finding an efficient and reliable water supply is a real challenge as to what we hear from miners. The water is also an essential tool in spotting the opals among the washed material. This is because the strong display of color is even more apparent when the gemstones are wet,” explains Alexander Kreis.
As the Gemological Institut of America (GIA) reports: “A regional drought is one of the major obstacles for opal mining. The drought … has lasted for several years, and finding a water source is a problem to many miners.”
Due to the drought, mining has become more difficult and it remains to be seen as to how negatively it will impact the remaining mining efforts any further. Making a scarce gemstone even scarcer.