Most retail jewelers are engaged in eco-friendly or socially responsible practices in some way: They carry a designer who uses recycled metals, or they can prove their diamonds do not come from conflict areas. But a small group of dedicated retailers is finding that education is the best way to court the socially conscious customer.At Chicago-based Leber Jeweler, a third-generation family business recognized as the first wholly dedicated socially conscious and eco-friendly fine jewelry store in the United States, owner Brian Leber and his wife, Joanne, decided to handcraft their own ­jewelry