RAPAPORT... Stuller, a provider of goods and services for jewelry professionals, has named Guy Borenstein as its senior gemologist.Borenstein has 15 years of gemology experience under his belt, including stints as vice president of gemological services at Gemewizard, and as chief gemologist at the European Gemological Center and at GWLAB laboratories, an independent chain of labs."Guy is a world-class talent, highly respected among leading gemologists," Stanley Zale, Stuller's vice president for diamond and gemstone procurement, said Monday.Stuller was founded more than half a century ago. Its core product categories include bridal jewelry, wedding bands, and fine jewelry.Image: Guy Borenstein. (Stuller)