These earrings are modeled after those worn by Erza Scarlet of Fairy Tail. They make a great cosplay accessory when you connect hoop earrings and jump rings (not included) to make a complete pair of earrings. For the best look, get Stainless Steel or Silver. However, both of these are quite heavy -- they are great for professional photoshoots, but a poor choice for three days at a con!
I suggest Alumide, especially Polished Alumide, for a metallic finish without as much weight. Just be aware that Alumide can be brittle, so keep it gentle.