October birthstone

OPAL

This gem’s play-of-color effect makes it a favorite for jewelry with a fiery, shifting glow.

"October birthstone" is a straightforward clue asking for the gem associated with that month. The answer is "OPAL," a colorful stone known for its shimmering, iridescent play of light. Some might think of "tourmaline" as another October birthstone, but "opal" is the more widely recognized and classic choice. The clue relies on general knowledge rather than wordplay, making it a direct definition.