All Kristina Collection jewelry is hypoallergenic and nickel-free, safe for sensitive skin. Metal: a combination of memory wire and metal components, which are made from Tombac, a brass alloy containing copper and zinc. Each wire is cut and formed by hand and the pieces are then soldered together. Coating: black enamel. The jewelry features both Czech and German glass beads. These beads undergo many processing steps, including heating glass and pressing it into molds, cutting and polishing, and adding a frosted finish using a tumbler with sand and water.