The cinder cone in Clayton Valley, looking north across a lithium brine pond, in which the cinder cone is reflected. Clayton Valley is the site of the largest lithium mine in the United States of America. It is an unusual mine in that the lithium occurs in groundwater in sediments that fill the valley. The lithium-rich water is pumped to the surface and partially evaporated, past the saturation point for halite (NaCl), the salt that coats the rocks in the foreground of this picture. The lithium-rich brine is then processed to produce useful products for batteries, medicines, and other uses.