This appears to be a piece of silver or gold jewelry used to fasten a cloak or cape.

In addition to this mundane task, it can absorb magic missiles of the sort generated by spell or spell-like ability. A brooch can absorb up to 101 points of damage from magic missiles before it melts and becomes useless.

Prerequisites: Craft Wondrous Item, overland flight, permanency.
Cost to Create: 500 gp (plus 500 gp for base item), 40 XP, 1 day.