Definitions for "Artificial toning"
coloration added to a coin by treatment with chemicals or other "doctoring"
Adding color(s) to a coin by various treatments with chemicals, heat and other methods in an attempt to increase its value. While a coin with natural toning may at times provide exceptional eye-appeal and command higher prices than an untoned specimen, a coin known to have been artificially toned (a deceptive practice) will bring much lower than usual prices.
Addition to the surface of a coin by chemicals and or by heat.