I've read the term "fish eye" in the Rocky Talky forum, and I've never understood what it meant. Does the spinel on the right have a fish eye? What about the cut is making it look like that?
I guess by the definition of a gemstone with a big window, a big table, a shallow cut, and weird leakage around the edge then yes it is, I think gem dealers and diamond dealers have different definitions of "fish eye" gemstone dealers don't use that term much and when they do I think they mean any stone that is shallow with a huge window like an eye in the centre - in diamonds generally the pavilion is shallow and the internal reflection of the girdle can create a weird ring in the centre if the diamond particularly if the stone also has a big table and a decent sized girdle. Diamonds with classic fish eye to look like this;