Jewelers must say whether diamonds are mined or synthetic: U.S. FTC

(Reuters) - The U.S. Federal Trade Commission, which investigates allegations of deceptive advertising, said on Tuesday that it has sent warning letters to eight companies to insist that they distinguish in advertisements between diamonds that come from mines and those made in laboratories. The FTC said that it had found instances where the eight companies advertised diamond jewelry “without clearly and conspicuously disclosing that the diamonds are laboratory-created,” according to the letter. The agency declined to identify the recipients of the letters. An unredacted version of one of the letters seen by Reuters identified that recipient as Diamond Foundry, a California company that makes laboratory diamonds.