黒鉛 is read as こくえん (kokuen) and means graphite.
こくえん
kokuen
くろまつ
black pine (Pinus thunbergii)
くろいきり
thick fog (of suspicion)
くろまく
black curtain
くろしお
Kuroshio Current
くろざとう
(unrefined) brown sugar
こくたいほうしゃ
black-body radiation
こくりゅうこうだいがく
Heilongjiang University
くろしゃつたい
blackshirts (Italian fascist group)
くろだいず
black soybean
こくえい
silhouette
くろめまめ
black-eyed pea
こくりゅうかい
Black Dragon Society (1901-1946)