durain

noun

1. (countable, uncountable)A type of coal.

   “The comparative absence of durain in many American coals caused some confusion in early attempts to correlate the English and American systems of nomenclature, since the duller portions of the American coals were at first compared with the English durains, whereas they should have been compared with the duller portions of clarains.”

   “Bands are visible in the coal from this seam, and there are more durain and fusain parts of coal than vitrain and clairain.”

   “The more durain-rich eastern Kentucky coal, with a higher proportion of inertinite- and liptinite-rich microlithotypes within the relatively low-HGI dull lithotypes, did not show as great a shift toward inertinite concentration in the fines as did the brighter western Kentucky coal.”