While the Tavernier Blue has been established as the “grandparent” of the Hope diamond, the only firsthand historical documentation for it is a 17th century line drawing of questionable accuracy. It has been suggested that the diamond was crudely cut, conforming to the shape of the original crystal. If this is correct, then it should be possible to correlate the facets on the Tavernier Blue to the faces of a diamond crystal, and thus gain information on the crystallography of the original rough. This study used this information, the original drawings, and a computer model of the French Blue diamond generated from the laser scan of a recently discovered lead cast, to generate a computer model of the Tavernier Blue. This new model completely encloses the computer model of the French Blue, conforms to Tavernier’s physical description, and establishes the orientation of the finished diamond within the original diamond crystal.