Bright coal definitions

bright coal

(from the article `coal`) ...coal type is also employed to distinguish between banded coals and nonbanded coals ( table). Banded coals contain varying amounts of vitrinite and ...
Found on http://www.britannica.com/eb/a-z/b/112

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bright coal

coal consisting of alternating layers of clarain and vitrain.
Found on https://www.infoplease.com/dictionary/bright-coal

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