This is a hand-forged brooch made of heavly twisted carbon steel treated to look like wrought-iron in the Celtic style. Brooches of this style were worn in Celtic and Germanic countries since pre-Roman times. It is worn with a a loosely woven blanket-style cloak where it is easy to pierce the fabric with a thick pin like this.
Overlap the two layers of the fabric and run the pin through both layers. Then fold the crescent section over the fabric until the curly ends are lower than the pin. Turn the crescent part until the pin is locked in place and secure.
Dimentions: 4" by 3.25"