Antique stud button, which I believe is red agate but could possibly be glass. This is overlaid with a molded and engraved fern leaf. Metal rim and back, with stud type shank. Backstamped: JEFFREYS PATENT BI-CLIMAX. The top of the shank has a single flap to push into button hole, then turns round to become a double flap to hold it secure.

Size 3/4” (1.9 cm)