Ridco designs and manufactures diamonds, gemstones and Black Hills Gold jewelry. Ridco offers a lifetime diamond guarantee that includes a lifetime replacement program, trade-in options, free sizing and free re-tipping. Ridco also uses diamond view, laser welders and laser ID (small number etched into the girdle of a diamond) with its jewelry. Ridco s gemologists and goldsmiths grade and laser loose diamonds that are purchased form the world diamond centers. Gemologist grade each diamond to determine its value by using the 4 c s - carat weight, clarity, color, and cut. In 2002, Ridco was ranked 19th by National Jeweler s as one of the top 40 jewelry chains in the nation. The company was founded by Jesse Riddle more than 45 years ago and now has nearly 50 stores in 12 Midwestern states. Ridco s manufacturing center is located in the Black Hills of South Dakota.