The Ethiopian Welo opal mines were first discovered in 2008 in the district north of the capital of Addis Ababa (although opal was said to have been discovered in the 1930's elsewhere in Ethiopia and minimal mining began in the 1990's):
The USGS estimates 2012 production of Ethiopian Welo opal to be 14,000 kilograms or 31,000 pounds. This estimation would change Australia's purported 95-97 percent of the world's opal production. There is not much information currently available about the Ethiopian Welo opal mines. Perhaps my daughter, Zoe, can make a field trip to the north to discover more about their deposition (or I could visit her and the opal mines!). I am quite curious about the similarities between the depositional environments in Australia and Ethiopia.
Opal is a hydrated amorphous form of silica with a water content ranging from 3 to 21% by weight. Because of its amorphous character, it is classed as a mineraloid, unlike the other crystalline forms of silica, which are classed as minerals.
Australian opal is generally of a higher water content than the Ethiopian Welo opal. It is also generally found in deeper environments. Opals which get too dry are said to "craze." Often gemologists store opals in water to keep them hydrated. I take mine swimming.
This four minute long video of Welo opals is worth a look, oh pals!
I like the fire and the setting of this Ethiopian opal.
Speaking of Ethiopia, here's the Peace Corps group arrival at the airport in Addis Ababa. Where's Waldo (er, Zoe?!) What an enthusiastic bunch (especially just after a 13-hour plane ride)!