In this thesis improvements are done to Glyptics Portrait Generator, which is an application for rendering an engraved gem. A technique is implemented to simulate subsurface scattering in translucent materials, which is required to accurately render many materials used in glyptic art. The existing gem materials are replaced by more realistic marble and multilayered agate materials. This thesis also covers the usability testing, the feedback analysis gives solutions to some problems that arose during the testing.