The Federal Trade Commission this week sent eight letters to jewelry marketers warning them that some of their online advertisements of jewelry made with simulated or laboratory-created diamonds may deceive consumers, in violation of the FTC Act.

The letters note that in July 2018, the FTC issued updated “Guides for the Jewelry, Precious Metals, and Pewter Industries” that provide marketers with information on how to make non-deceptive representations about jewelry and related products, including mined, lab-created, and simulated diamonds. Failure to follow the guides, the staff warned, may result in enforcement actions if the FTC determines the companies engaged in unfair or deceptive acts or practices. These actions could result in civil penalties if the company engaged in such practices knowing that the Commission has already deemed them deceptive in earlier litigation.