opaline

adj

1. Resembling opal in having a milky white iridescence.

   “She was so alive that night, opaline points in her eyes, mouth parted to bare her teeth.”

noun

1. (countable, uncountable)A clear to white liquid secreted by sea hares (genus Aplysia) that becomes viscous upon contact with water.

   “The attack on a sea hare by a spiny lobster causes release of the whitish opaline, followed the co-release of both opaline and ink.”

2. (countable, uncountable)Any of several minerals resembling opal, including a variety of yellow chalcedony.
3. (countable, uncountable)Synonym of opal glass.