Neat vintage Brass Brooch/Pinback from the 1970's.
It reminds me of the Star Trek 'swoosh' communicator pins, though I doubt that was the intention of the design.
The pin is not flat, but is actually shaped on a curve. I have attempted to show the curve as much as possible in the photos, but it isn't exactly a deep curve.
There is a 'locking' 38mm pinback soldered to the back on the long side of the curve, as shown. The pinback is in a dull silvertone, possibly old nickel silver.
The brass is naturally tarnished, so the color is a patina brown with a brassy yellow peeking out.
This pin is certainly polishable if you desire a high shine yellow brass.
This would make an excellent base for bead embroidery, or as a glue pad for crystals, or a base for Crystal Clay in my opinion.
You will receive 1 brooch.