from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A dark green or greenish-black silicate mineral, Be2FeY2Si2O10, containing several of the rare earths in combination with iron.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A dark, vitreous mineral that is a complex mixture of silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron, with the chemical formula (Ce,La,Nd,Y)2FeBe2Si2O10.
from the GNU version of the Collaborative International Dictionary of English
- n. A mineral of a nearly black color and vitreous luster, and consisting principally of the silicates of yttrium, cerium, and iron.
from The Century Dictionary and Cyclopedia
- n. A mineral, a silicate of the yttrium and cerium metals, containing also beryllium and iron.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a mineral that is a source of rare earths; consists of silicates of iron and beryllium and cerium and yttrium and erbium
In 1879 a Swedish chemist named Lars Fredrik Nilson was looking for rare earth elements in the minerals euxenite and gadolinite when he discovered erbium and ytterbium; scandium was later separated from the ytterbium.
In this mineral - later called gadolinite, after him - he had found a hitherto unknown earth, the so-called yttria.
Yttria is found in gadolinite and some other rare minerals.