Tassie, James, 1735–99, Scottish gem engraver and modeler. At first a stonemason, he went to Dublin, where he assisted the gem engraver Dr. Henry Quin. With him Tassie invented an especially hard and fine-textured white enamel for making replicas of gems. In 1766 he went to London, where he duplicated famous gem collections, notably many thousands of specimens for Catherine the Great. R. E. Raspe prepared a catalog of Tassie's work in 1791. Working often for Wedgwood, he made the first plaster cast of the Portland vase. Many of his portrait medallions are in the Scottish National Portrait Gallery, Edinburgh.