Searching Necklace

Recently, Objects and Elements website posted a tutorial about riveting domed metal to a flat surface. How serendipitous, I was just starting up a piece where I'd be doing this! Here is my submission to this challenge. The larger found metal piece was somewhat domes already. I used the method discussed to refine the curve, and riveted using a wire rivet strengthened by a brass tube.

This piece, 'Searching' was made with lots of found metal pieces. I think the top one is from some kind of audio equipment? No idea what the bottom once was... any ideas out there? Other found pieces include a round piece, and also a lens from a friend's broken camera. It works pretty cool as both a necklace and a mini magnifying lens.