Abstract: A fuel block containing concentrated combustibles is provided in a stackable, clean package which is readily ignited, and after an initial ignition burn, is consumed from the inside out with minimal smoke release. In the preferred form of the invention, ends and sides of the block have parallel faces, but the base is concave to permit an air entry passageway when the block is so positioned and burned on any generally flat surface. The top or opposite face is congruently convex to the bottom face permitting stacking of individual blocks both in storage and use. When stacked in combustion use, interior air passages or flues both horizontal and vertical, through the exterior faces of the individual block align to provide a "coking" action, as is also the case when burning of an individual block alone.The block is formed principally from coal mine particulates, coke particulates, etc.