Method, for coloring gemstones, uses a ceramic plate to support a stone on its flat side, which has been sprayed with ferrous oxide, to be fired at a high temperature to give a color diffusion

摘要

To treat precious gemstones, to give a variety of color effects, a topaz stone (3) for example is sprayed with ferrous oxide, and placed on a ceramic plate (1) with its flat side (2) downwards. It is fired at a temperature of 1050 degrees C, and then continuously cooled to give the stone a colored diffusion.