A dark brown to black combustible sedimentary rock that is used as a fuel source. It accounts for the generation of about 55 percent of the total electricity output in the United States. The United States has 30 percent of the worldÂ’s bituminous and anthracite coal reserves, more than any other country except China, which consumes nearly all of its own production. Coal futures are traded on the New York Mercantile Exchange (NYMEX). Coal futures are a relatively new addition to the NYMEX, with trading beginning only in the late 1990s. Its trading symbol is QL.