Defn: A mineral occurring as an aggregation of minute scales having an olive-green color and pearly luster. It is a hydrous silicate of aluminia and iron.
THURL
Thurl, n. Etym: [AS. a hole. *53. See Thirl, Thrill.]
1. A hole; an aperture. [Obs.]
2. (Mining) (a) A short communication between adits in a mine. (b) A long adit in a coalpit.
THURL
Thurl, v. t. Etym: [See Thrill.]
1. To cut through; to pierce. [Obs.] Piers Plowman.
2. (Mining)
Defn: To cut through, as a partition between one working and another.
THURLING
Thurl"ing, n. (Mining)
Defn: Same as Thurl, n., 2 (a).