Antique metal alloy button - tombac or similar. Flat shape with engraved design, and stamped textured rim. Plain flat back with cone holding a metal loop shank. All the signs of an early button - 18th or early 19th century. Sadly the front surface is badly corroded. I have not attempted to clean it. The back still has much of the shiny tin coating (see last photo) which shows how shiny it once would have been.

Size 1.2” (3.1 cm)