A miner's term long used in Eastern United States and Scotland for certain hard dull coals with a distinctive type of fracture. Splint coals are irregular and blocky, with an uneven rough fracture, grayish black in color and of granular texture. Splint coals are banded coals. Coals containing more than 5% of anthraxylon and more than 30% of opaque attritus determined by microscopic examination are classed as splint coal. The content of anthraxylon and opaque matter is determined perpendicular to the bedding across the entire thin section (2 to 3 cm in width). The opaque attrital portion of the splint coal may be intercalated with fine, hairlike streaks of anthraxylon. It occurs mainly as bands and benches in otherwise bright-banded coal and is wide-spread in bituminous coal seams. Corresponds either to duroclarite or, more frequently, to clarodurite according to the ratio of vitrinite and inertinite. May also correspond to vitrinertite.