N.Y. Gen. Bus. Law § 229-j

§ 229-j. Sale of artificially colored diamonds. Any person, firm,\ncorporation or association, and any agent or employee thereof, who or\nwhich shall knowingly sell or offer for sale any diamond which shall\nhave been artificially colored or tinted by coating, irradiating,\nheating, nuclear bombardment or by any other means, without disclosing\nin writing to the purchaser, or prospective purchaser, that such diamond\nhas been artificially colored or tinted, or without disclosing in\nwriting that the artificial coloring or tinting of such diamond is not\npermanent, if that be the fact, shall be guilty of a misdemeanor.\n