Wal-Mart, the nation’s largest jewelry retailer, specializing in low- to mid-market jewelry, is adding Keepsake’s line of 14-kt. gold and diamond jewelry to its inventory. The retailer has long carried diamond jewelry, but the Keepsake addition signals an upgrade in quality for the discounter. Keepsake’s higher quality stones carry a retail price of $199 to $899. The line includes bridal sets, earrings, necklaces and rings. The shift to higher quality and brand name jewelry is one that analysts predict will become a trend in discount department stores.