Emily Dickinson Lexicon

YT-TRO-CE'RITE, n.

A mineral occurring very sparingly at Finbo and Brodbo near Fahlun, imbedded in quartz. Its color is violet-blue, inclining to gray and white. It is sometimes white. These colors generally alternate in layers, in the same specimen. It is said to consist of fluorid of calcium, fluorid of yttrium, fluorid of cerium, and oxygen combined with one or more of these metals.