The departure of Sergey Vybornov from Russian diamond producer Alrosa has slowed the movement of the International Diamond Board, the pan-industry initiative that is meant to underwrite generic marketing for diamonds.

Vybornov was a prime backer of the IDB. But a letter, signed by representatives from diamond miners De Beers, Rio Tinto, and BHP, said its launch would be postponed so "Alrosa has sufficient time to review its plans and confirm its participation."

The letter continued, "The immediate impact of this decision will be the postponement of the appointment of a CEO to run the IDB."

One name not on the letter: Harry Winston, which, like Alrosa, was an early IDB backer. This could be a sign that its commitment also is wavering. Still, people behind the idea were optimistic it would eventually launch.