This is a lovely, circa 1900, stick pin, unmarked, but tested, 15 ct. gold. It has a lovely design of leaves, a thistle, and a shamrock. It has a safety at the bottom, which I'm sure has been added at a later date. The stick pin measures 2 and 1/2 inches North to South, and 1/2 inch east to West.
15 ct Stick Pin, Thistle and Shamrock, Victorian