A hard, black, lustrous coal that burns efficiently, containing a higher percentage of fixed carbon and a low percentage of volatile matter differing from bituminous, and generally having a heating value of 11,000-12,000 Btu/lb. Commonly referred to as hard coal; it is mined in the U.S., mainly in eastern Pennsylvania, although in small quantities in other states. Most of the anthracite is used as a fuel in household heating systems. When anthracite burns, it produces almost no smoke.