im guessing but it could be as much as 25%-i had a chipped stone repaired-small chip but recut/polish used almost 1/2ct lost material-was an andesine which is soft to start with-u said cussion to a round-lots of corners-steve...
Ditto above. Unless you start w/a honkin' big stone, you might end up w/something pretty small. And what would the re-cut do to quality -- window, extinction, etc.?
Indy, I had a 9 x 11mm oval (I don't remember the depth dimension, but it was a very deep keel cut pavilion), and ended up with a 6.7mm cushion. Hope that offers some perspective.