Rough Ethiopian Welo Opal Grading Criteria
Ethiopian Welo Opal Grading Criteria
- AAA grade: We get only a tiny amount of this grade…perhaps only 6 ounces a year in the past. This grade has to have spectacular colors…very bright and vivid patterns. And the material will have to be free of matrix or as free as possible without damaging or removing the precious opal. No fractures here or if there are any at all they will not affect the overall yield of the stones. Very special high yield opal. Most of this opal is sold before it can get to our website. Some blacks can be found in this grade. No internal matrix inclusions with the naked eye.
- AA grade: Very similar to AAA grade but colors will not be quite as stunning. There will also be very little matrix on the stones and they will be exceptionally high yield opals as in the AAA grade. No fractures here or if there are any at all they will not affect the overall yield of the stones. No internal matrix inclusions with the naked eye.
- A grade: Very nice opals. But there will be some milky stones with play-of-color in the lot. And some of the stones in this grade will have cracks. The stones exhibiting a crack will still be candidates for cabochon cutting but may need to be cut into 2 or more stones instead of 1 stone. Colors will be vivid and bright in most stones, but the overall yield will be less than in the AA grades of Welo opal. More irregular shaped stones in this grade that will affect overall yield if cut into cabochons instead of carved or contoured.
- B Grade: Low grade opals with subdued play-of-color. There will still be some bright opals here, but overall the yield will be much lower than higher grade stones. I try to pick stones for this grade that will still work into a cabochon even though the colors may not be bright.
- C Grade: At this time I am not selling any “C” grad opal. But my plans are to offer lower grade opal at a much reduced price….perhaps $25.00 to $50.00 per ounce.
- Mine Run Grade: This grade is usually characterized as a true mine run with a great variety of sizes and colors. My supplier in Addis Ababa said this is an ungraded selection as it comes from the miner. I don’t grade this except to add higher grade material to any parcel that I think doesn’t meet my standards.