Method of coloring cut gemstones

摘要

A method of coloring cut gemstones introduces metals or metal oxides into a surface layer by means of heat treatment. During the heat treatment the gemstones are laid on a solid plate and the metals or metal oxides form a substantial constituent of the plate. The surface of the gemstone is protected from direct content with the metals and metal oxides in the plate by a layer containing non-coloring oxides.