Mining, manufacturing and construction accounts for about 39% of the GDP, with manufacturing alone accounting for 32%. This has remained steady for the past few decades. Minerals is one of the state’s two main natural resources. Mining is a traditional economic activity for the state. There are ten mining districts in the Sierra Gorda alone producing lead, silver, zinc, copper, gold, mercury and antimony. Nonmetallic products include marble, kaolin, sandstone, and more. Opals are a distinctive state resource. State and local governments, in partnership with private industry, actively promote foreign investment into the region. The priority of the state government is to encourage industries which use low levels of water for environmental reasons. These have mostly been auto parts, food processing and electronics. Other major industries include chemicals, plastics, textiles, paper products and printing and wood products. Most are micro and small sized operations.