New York Laws
Article 13 - Silver, Gold and Diamonds
229-J - Sale of Artificially Colored Diamonds.

ยง 229-j. Sale of artificially colored diamonds. Any person, firm,
corporation or association, and any agent or employee thereof, who or
which shall knowingly sell or offer for sale any diamond which shall
have been artificially colored or tinted by coating, irradiating,
heating, nuclear bombardment or by any other means, without disclosing
in writing to the purchaser, or prospective purchaser, that such diamond
has been artificially colored or tinted, or without disclosing in
writing that the artificial coloring or tinting of such diamond is not
permanent, if that be the fact, shall be guilty of a misdemeanor.