Vintage Art Deco Black Bar Brooch, Early Plastic

This vintage brooch is black plastic with coloring (paint?) in the art deco style. It is made to look like carved Bakelite, but indeed is not Bakelite. It is very light (as opposed to heavy) and feels like it is hollow. Indeed, it smells like celluloid to me (which could make it quite early). It has an early safety pin type c-clasp.