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

摘要

The invention is a multicolored reflecting surface that can be mounted beneath a lens for facilitating the grading of a gemstone's brightness and symmetry. The multicolored reflective surface may be a disc that has an opening or aperture surrounded by multicolored concentric rings through which the gemstone is viewed on the object side of the lens. Alternatively, the multicolored reflective surface may be a cylinder formed of multicolored bands through which the gemstone is viewed. Light reflecting from the multicolored rings or bands creates specific colors on the gemstone that allow symmetry and brightness of the stone to be evaluated.