Device for judging symmetry, brightness, and efficiency of light return in precious stones

摘要

The invention is a multicolored reflecting disc that can be mounted to a lens for grading gemstone brightness and symmetry. The disc has an opening or aperture through which the gemstone is viewed on the object side of the lens. The aperture is surrounded by multicolored concentric rings which face the gemstone. Light reflecting from the multicolored rings creates specific colors on the gemstone that allow symmetry and brightness of the tone to be evaluated.