Very nice blue Opal doublet set in a 10k vintage setting . It would fit a lady with petite hands as a pinky ring or you could have it sized to fit your needs . In the picture you see what looks like cracks but the top is smooth, it is called crazing common with Opals . it has been set on what I believe to be another stone or it is part of the Opal it self hence the darkness from the underside of the stone , since Opals are delicate it is a common practice to find this especially on larger thin Opals I I believe this to be a Peruvian Blue Opal, please don't quote me $350