Main Entry:

opal

Pronunciation:

\ˈō-pəl\

Function:

noun

Etymology:

Latin opalus, from Greek opallios, ultimately from Sanskrit upala stone, jewel

Date:

circa 1586

: a usually amorphous mineral that is a hydrated silica softer and less dense than quartz and typically with definite and often marked iridescent play of colors and is used especially as a gem