Vapor Crystal Growth System developed in IML-1, Mercuric Iodide Crystal grown in microgravity FES/VCGS (Fluids experiment System/Vapor Crystal Growth Facility). During the mission, mercury iodide source material was heated, vaporized, and transported to a seed crystal where the vapor condensed. Mercury iodide crystals have practical uses as sensitive x-ray and gammax-ray detectors. In addition to their excellent optical properties, these crystals can operate at room temperature, which makes them useful for portable detector devices for nuclear power plant monitoring, natural resource prospecting, biomedical applications, and astronomical observing.