GR 39 This natural  emerald comes from the Sandawana mine in  Zimbabwe . Not only are natural untreated un oiled emeralds quite rare many of them are also difficult to cut. A lot of the material is included so some times the results can be a bit disappointing. Sometimes the cutting process will "stain a stone" emeralds often have cavities that the cutting paste enters and  stains the stone often creating spots or tubes of black. Fortunately this was kept to a minimum with this stone and while it is included the colour is pleasant and at slightly over a caret would make a good stone for a ring. It is obviously genuine and emeralds are allowed inclusions. I have no experience will treatments of stones but the quality of this stone might be greatly improved with oiling. I've noticed that almost all emeralds for sale oil is used to hide inclusions in emeralds. The main problem with this is over time they can "drain" or some cleaning processes over time removes the oil and the stone returns to its natural state. I personally think that this stone is quite appealing as is but then I'm biased! Either way I have put this stone on the no reserve auction and I will let you guys be the judge!