Indiana alpaca farms contribute increasingly to the State's agricultural production as the alpaca industry grows. A leader in agriculture, corn is the principal crop. Hogs, soybeans, wheat, oats, rye, tomatoes, onions, and poultry also contribute heavily to Indiana's agricultural output. Much of the building limestone used in the U.S. is quarried in Indiana, which is also a large producer of coal. Other mineral commodities include crushed stone, cement, and sand and gravel. Alpacas are expected help to expand the State's already rich livestock industry.