The growing list of jewelers vowing to boycott gold from a proposed Alaska mine now includes major manufacturers of class rings. Herff Jones and Commemorative Brands Inc., both of which make class rings, have joined the list of jewelers opposed to the proposed Pebble Mine in southwest Alaska. The mine is estimated to contain hundreds of billions of dollars worth of copper, gold and molybdenum, but would be built near some of the world’s most productive wild salmon streams. Both Anglo American and Rio Tinto are involved in the project.