Opal

o'pal, n. A mineral consisting of silex in what is called the soluble state, and usually a small quantity of water: the $>recious opal presents a peculiar play of colors, and is esteemed as a gem. — Opalesce/', -pal-es', v. i. [-esced (-est1'), -escing.] To give forth a play of colors, like the opal. — Opalescence, -es's ens, n. A reflection of a milky pearly light from the interior of a mineral.