What is white opal? Where is white opal found? How is white opal mined? How is white opal cut? How is white opal valued? FAQ: how is white opal different to black opal and boulder opal?
What is white Opal?
White opal is a type of Australian opal that is found in South Australia.
Australian White Opal gets its name from the white body colored common opal that hosts the bands of precious opal trapped inside the common opal nuggets.
White opal is sometimes called ‘milky’ opal.
Precious opal is opal with complex colors and patterns, often described as ‘play of color,’ that forms in seams, bands, veins and pockets within the host (common) opal or host rock.
Common opal is opal that does not have ‘play of color,’ and is usually only one color at a time.
Common opal and precious opal have the same chemical composition but vary microscopic structure. For this reason, they work with light differently. Learn more about what is opal here.
White opal is precious opal hosted by white common opal.
White opal colors are dazzling, delicate and light. White opal is relatively easy to identify because of its white background. The predominant color in white opal is pink/red however when it comes to opal, color is not a stationary thing. Opal color can go from light to dark and present in patterns that range from pinfire to block (and everything in between).
Green is another opal color that occurs somewhat frequently in white opal.
Blue, purple opal color, occur less often in white opal.
Where is white opal found?
Australian white opal is found near and around the isolated township of Coober Pedy in South Australia.
Opal was discovered in the late 1800s and early 1900s and the rest is history. While Coober Pedy is famous for its opals it is equally as famous for its quirky style. In Coober Pedy, people live underground [pic] to escape the extreme desert heat and the ground surface looks like a moonscape. [pic].
In the past, the Coober Pedy white opal fields have been the most productive opal fields in Australia however in recent time production of opal has slowed down across the board.
South Australian Opal Fields – A moonscape
Cosy underground living in Coober Pedy
How is white opal mined?
Australian white opal is mined in much the same way as Australian Black opal. Miners sink shafts and haul the waste dirt up on a windless (in the old days) or motorized winch (the modern day) in search of the “level’. Opal is found on levels (band/shelf) in clay beds embedded in the geological strata. The little nuggets of opal are found studded in the clay beds. When the miner gets down to a level where there’s color they proceed very very carefully. When a miner strikes color, it’s Eureka!
How is white opal cut?
Australian white opal is cut in much the same way as Black Opal. The nugget of opal is wet and inspected. A cutter studies the nugget to decide on a plan of attack. As the precious opal (color) is only a band it is ‘captured’ in common opal. Removing the common opal above the band of color is called facing down or ‘rub’. Before a cutter starts facing down, they must decide which side to face down or ‘rub.’ Once the color face is exposed the cutter shapes the gemstone, polishes it and finishes the back.
How is white opal valued?
White opal is valued on color pattern and size.
Vibrant, strong, colors and complex patterns are the top order but there are infinite variations of these three broad groups which means grading and pricing is most done by experts who have experience in the industry.
White Opal gemstones are usually sold by carat weight.
FAQ: How is white opal different to black opal and boulder opal?
The three generic types of opal are related in that they all share the same chemical composition [SiO2nH2O] they differ according to where the SiO2nH2o lay down. Geography is the key defining factor.
White opal and black opal is found in common opal nuggets found in clay beds within the geographical strata. Boulder opal is opal hosted by rock. Learn more about Boulder Opal here.
The key defining feature between White Opal, Black Opal and Boulder Opal is the host opal/rock.