This vintage inlay earrings are from Mexico. They are made from Alpaca which is an alloy of tin, copper, zinc, and nickel. Each earring has blue stone inlay (some folks call this turquoise but I cannot be sure what stone was used) and black enamel. They are stamped "ALPACA MEXICO" on the back.
Please note that we have photographed these earrings with the original fishhook earwires which are a little misshapen (we left them on for the collectors who want all original parts). We would be happy to change them to new antiqued silver plated fishhooks for you. We have also left them unpolished to keep the aged patina, but you can polish them up if you like!