This is anthracite coal, stove sort, from Pennsylvania. It is sold in one pound bags.
Anthracite coal, or hard coal, has the highest carbon content, the greatest hardness, and the fewest impurities.
This is "stove coal". Stove is a measurement of size, not content. The standard sizing of stove coal is 1 9/16 to 2 7/16 inches (39.70 to 61.30 millimeters). Some random pieces measured 0.5 to 2.5 inches.