This stone is very rare. This is a cat's eye aquamarine- (March birthstone) with chatoyancy. That means that the light spills across the surface and gives it a line of brightness that travels across the cabochon when you move it in the light. This is the sort of gem that makes gemologists drool. Not only does it have a cat's eye in ONE direction, but in sunlight it has a two of them, forming a really definite cross. I have seen less than ten of these in my whole career and never one like this, with two chatoyant directions. The gemstone has an ethereal quality to it. I set this beauty on a half-round inside band (meaning it is rounded on the inside and super comfortable) with 18k yellow gold details on the side. These are a nod to architecture as they somewhat look like columns or coins on the corners of classic structures. Because of all of the care and attention I put into this, there are all sorts of important-looking hallmarks on the inside- a riot of information about its provenance. Aquamarine is the March birthstone. In a private collection. Am still on the lookout for another one of these aquamarines...