Earrings are cut and sanded, for smoothness, from 2 different tins. The 2 circles are riveted with an aluminum rivet.
Ear wires are gunmetal-plated brass, 15mm fishhook with open loop, 21 gauge. 
Each pair come with silicone clear earring backs. 
Earrings have been treated with a museum grade wax to protect and enhance, called Renaissance.
Some of the tins are vintage and have been lovingly used over decades. Therefore, there may be fine scratches or imperfections.