Sterling Jewelers Inc., the operator of Kay Jewelers and Jared the Galleria of Jewelry, is suing rival Zale Corp., alleging false and misleading advertising. Zale claims that its Celebration Fire diamond is “the most brilliant diamond in the world.” Sterling argues that the brilliance of a diamond is a recognized, scientifically measureable property within the jewelry industry and among jewelry customers and is therefore not a statement of subjective opinion. 

Zale says the advertising is based on testing by an independent laboratory and that the lawsuit is without merit. Sterling argues that the research behind Zale's claim was limited to diamonds from select leading national jewelry chains. Sterling states in its filing that Zale's claim is invalid unless its Fire diamonds have been tested against every other cut of diamond in the world. 

The lawsuit comes during the busy holiday season; November and December are the highest volume times of the year in the jewelry industry and Sterling is requesting a preliminary injunction to halt the advertising before court proceedings can be resolved.  Sterling seeks to recover an unknown amount of monetary damages from Zale.