This very unique brooch pin dates between 1910 to 1930's due to the tube and safety clasp design. I believe it is closer to 1910 due to the fact that the pin extends past the brooch.
This brooch is unmarked and has a hollow design that gives it a 3D effect with lots of intricate designs on the front side. Also has an attached piece that dangles and moves freely. Measures 2 2/8"H x 1 1/2" W.