gadolinite

gadolinite

[′gad·əl·ə‚nīt]

(mineralogy)

Be₂FeY₂Si₂O₁₀ A black, greenish-black, or brown rare-earth mineral; hardness is 6.5-7 on Mohs scale, and specific gravity is 4-4.5.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.