hawk's-eye

hawk's-eye

n
(Minerals) a dark blue variety of the mineral crocidolite: a semiprecious gemstone
References in periodicals archive ?
While studying the chemistry of hawk's-eye, a blue form of tiger's-eye, he found that the gem was almost entirely quartz but that it also contained fibers of crocidolite, an often bluish, iron-bearing form of asbestos.