n. [ L. opalus: cf. Gr. &unr_;, Skr. upala a rock, stone, precious stone: cf. F. opale. ] (Min.) A mineral consisting, like quartz, of silica, but inferior to quartz in hardness and specific gravity. [ 1913 Webster ]
☞ The
v. i.
n. (Min.) A reflection of a milky or pearly light from the interior of a mineral, as in the moonstone; the state or quality of being opalescent. [ 1913 Webster ]
a. Reflecting a milky or pearly light from the interior; having an opaline play of colors. [ 1913 Webster ]
n.
a. [ Cf. F. opalin. ] Of, pertaining to, or like, opal in appearance; having changeable colors like those of the opal. [ 1913 Webster ]
v. t.
n. [ Opal + -type. ] (Photog.) A picture taken on “milky” glass. [ 1913 Webster ]