Ro creates all of the molds, along with everything from start to finish, for his sulphides, and this amazing skull sulphide is no different. True to form for Ro, this is the most anatomically correct skull you'll ever find in a marble, sulphide or otherwise. It is truly amazing work, and this is also one of the rarest Ro Purser marbles you'll ever find! There are very very few of these out there, so grab this amazing piece of art glass marble history while you can! Signed 'Ro' on the bottom of the skull as part of the sulphide mold.