Rapid City's economy is diverse, but industry is a small portion, as is typical of many US cities in the 21st century. Heavy and medium industrial activities include a Portland cement plant (constructed and owned for 84 years by the State of South Dakota and sold in 2003 to Grupo Cementos de Chihuahua, or GCC, a Mexican-based conglomerate); Black Hills Ammunition, an ammunition and reloading supplies manufacturing company; several custom sawmills, a lime plant, a computer peripheral component manufacturing plant, and several farm and ranch equipment manufacturers. Of particular note, this city is the center for the manufacture of Black Hills gold jewelry, a popular product with tourists and Westerners in general. The city is the site of the only American manufacturer of stamping machines used for the labeling of plywood and chipboard products.