This is a vintage gold-tone tie clip featuring a banded agate or glass cabochon with striped black, white, and gray coloration, set in a decorative bezel. Here are the key details:

• Material: The setting appears to be gold-tone metal (likely brass or gold-plated base metal).

• Stone: The central inlay looks like banded agate, a naturally occurring variety of chalcedony known for its layered appearance. It could also be banded glass simulating agate, common in vintage costume jewelry.

Tie clasp is in good condition.  See photos for more details.