1/5/2024 0 Comments Ethiopian opalAnother concern is that some of the crystal opal produced at the deposits in Wollo is being darkened via a smoke treatment to resemble natural black opal. In addition, researchers have identified yellow-to-orange fire opal and crystal opal from Wollo Province as being more prone to breakage than the white opal from the same province. ![]() “Also, I’m concerned with the amount of drying and cracking from this material and its long-term durability.” “My concerns are based on the material being hydrophane and therefore losing color when submerged in water, with the possibility of the color not coming back or picking up dyes and lotions that will taint the base color of the opal,” Farnsworth explains. “We’ve seen little crazing in the tens of thousands of pieces we’ve worked with, and we’ve had no returns from our customers.”įrank Farnsworth, president of Idaho Opal & Gem Corp., Pocatello, Idaho, agrees that the Wollo Province opal is interesting from a scientific point of view, but his concerns outweigh his fascination. Mike Romanella, partner in Commercial Mineral Company, Scottsdale, Arizona, notes that although the Wollo opal does not have the 100 years of proven history the Australian opal has, his two-year experience with the material has been positive. Repetition of the test on five oval cabochons did not produce any sign of damage.” When the same experiment was conducted with oval cabochons from the Mezezo deposit and Australia, including one boulder opal, all samples broke. Not only are they stable, researchers say, they’re surprisingly tough.Īccording to Gems & Gemology, “Wegel Tena opals could sustain a fall from onto a concrete floor with no visible damage, even under the microscope. Laboratory testing of the Wollo opal revealed most specimens were resistant to crazing after repeatedly being immersed in water and dried out over a period of time. They describe this new Ethiopian opal find as different from the opals of Shewa Province. “Wollo opal should be recognized as a new type because it can absorb or lose water, affecting transparency and play-of-color when wet, but recovering all its qualities when dry,” report researchers. ![]() But the Wollo Province deposit was hailed as one of the most promising deposits of precious opal for the coming years in the Summer 2010 issue of Gems & Gemology and the Summer 2011 issue of InColor. Opal from Ethiopia that hit the market in 1993 from deposits near Mezezo, Shewa Province, has a tendency to craze. Fire and crystal opal, found in Mexico and the United States, is also of volcanic origin. The only other significant opal producers are Brazil and Mexico, and most recently Ethiopia - all volcanic environments. It is considered an important source of precious opal, which is produced in a sedimentary environment and has a proven track record of stability. Australia is the leading producer of opal, with more than 90 percent of the world’s supply. Opal is typically found in two geologically distinct environments: sedimentary or volcanic. “Opal in general is prone to break it’s basically a glass of sorts,” explains Bear Williams, director, Stone Group Laboratories, Jefferson City, Missouri. But other specialized opal dealers remain skeptical that this high-porosity, high-water-content hydrophane opal may in time crack or craze, which would endanger consumer confidence in opal and opal jewelry for the future.Ī gem like no other, opal is an amorphous form of silica related to quartz that contains a variable amount of water and often is very brittle and fragile. Researchers and some wholesalers in the gem trade hail the deposit’s significant quantities of high-quality play-of-color opal that is remarkably stable and durable. The mine produces mostly white, translucent opal, much of which has vivid play-of-color. ![]() The buzz in opal today is for gemstones from a new source in Ethiopia, discovered in 2008 near Wegel Tena, Wollo Province.
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