Associations, manufacturers, retailers, and consumers are expressing more interest in the origins of their materials. Here’s what it all means.It's a question that, in one form or another, has bedeviled the jewelry business for the past decade: Where do your jewelry materials come from?"You can go to Starbucks and know the origin of your coffee," notes Michael Rae, chief executive officer of the Responsible Jewellery Council. "But you can't go into a jewelry store and know the origin of one of the most ­significant purchases of your life."In the past, most jewelers tended to brush such queries aside. "It's impossible to know," they'd say. But that answer is now coming across as insufficient, even insincere. "The sad truth is that most consumers still cannot be sure where their diamonds come from," wrote Blood Diamond director Edward Zwick recently in the Huffington Post. And the press