The specific details of the process used to enhance color and clarity in GE POL diamonds have not been disclosed. However, a survey of U.S. patents and European patent applications reveals that General Electric has developed a variety of high-temperature annealing techniques at different pressures for enhancing the optical properties of polycrystalline synthetic diamond films and single-crystal synthetic diamond. These methods may provide important clues to the process being used to decolorize natural type IIa (GE POL) diamonds, that is, by reducing the structural defects associated with their brown coloration.
