Often alternatively referred to as phosphate rock, phosphorite is frequently associated with chert, shale, and sandstone. The phosphate that is contained in the rock is typically present in dense masses or nodules, which are the chief global resource exploited for phosphorous-containing fertilizers. Deposits of phosphorite can be found in various locations around the world, but the nation leading in both production and consumption of the rock is the United States. In recent years, the North American country as well as several other important phosphorite mining nations began reducing export of the raw material, however, to safeguard reserves for their own manufacture of phosphorous products, a large portion of which enter the international market, where they command higher prices than unprocessed goods.