Crossword Genius

Autumnal birthstone (4)

Ross

I believe the answer is:

opal

'autumnal birthstone' is the definition.
(I've seen this in another clue)

This is all the clue.

(Other definitions for opal that I've seen before include "Milky-white gem" , "Quartz-like gemstone" , "One's stony" , "Form of hydrated silica, often used as a gemstone" , "Gem with delicate colours" .)

I've seen this clue in the Universal, the USA Today, The Wall Street Journal, the Thinks.com and the King Feature Syndicate.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.