The FTC recently sent warning letters to eight marketers of lab-created diamonds concerning implied claims on social media that their diamonds are mined (rather than simulated) and that their jewelry is “eco-friendly” or “sustainable.” The FTC’s Jewelry Guides contain specific requirements for disclosing lab-created properties and avoiding misperceptions that gems are natural. Moreover, the FTC’s Green Guides require that marketers have a reasonable basis for all express and implied environmental benefits claims.