The bounty of opals streaming out of Ethiopia has turned the tide for the gem. Once considered unlucky, it’s now a designer favorite for its availability, still-affordable pricing, and flickering play of color.In early 2008, farmers in Ethiopia’s Wollo province stumbled upon a cache of opals with an enchanting white-to-yellow-to-brown play of color. Unbeknownst to them, their find would kick-start a rush on the iridescent gems that’s still going strong today.“The Ethiopian find has been the most important [opal] source from a volume standpoint for at least the past five years,” says Stuart Robertson, G.G., research ­director for Gemworld International Inc. in Glenview, Ill.By all accounts, the availability of Ethiopian material has stoked demand for all kinds of opals (mainly Australian, though the gem is found in myriad locales ­including Mexico, Peru, and Turkey), resulting