Carder considered Intarsia to be his greatest achievement. In 1916, Swedish glassmakers had developed the Graal technique, in which colored reliefs were cased in crystal and the surface was then smoothed. Carder experimented with this technique in 1916 or 1917, and he started commercial production of Intarsia in the 1920s. He made bowls, goblets, and vases with a floral or foliate design in a thin layer of colored glass sandwiched between two thin layers of colorless glass. The vase shown here was made in an unusual combination of colors. The amethyst design is enclosed between two layers of French blue. Most of Carder’s Intarsia glass bears the engraved facsimile signature “Fred’k Carder.” This glass was not produced in large numbers, and very few examples are known today.