Jack Gredinger has been appointed executive director of "Leading Jewelers of the World," the planned network of some 300 upscale jewelers overseen by sightholder W.B. David. Susan Lebow has been appointed director of marketing for the program. Gredinger will oversee a relaunch of the "Leading Jewelers" program. Instead of a nationwide rollout, the program now will concentrate on building slowly, one local market at a time. The program also is unveiling a "Trust Mark" that participating jewelers can display. "We want it to be a symbol for the ultimate luxury shopping experience," Gredinger says. Gredinger formerly headed Hearts On Fire and the Independent Jewelers Organization.