1968 Copper Enamel Lincoln Penny Earrings. Prior to 1982 every penny the U.S. Treasury minted was 95% copper. Today pennies have a predominant zinc make up with minimal copper. Because of the high copper ratio these pennies have been heated with a torch making the metal more receptive to being domed/shaped. After the shaping process 4-5 layers of transparent enameling glass are sifted and then torch fired until the surface is glossy meaning the glass has melted and adhered to the copper. The shade is light raspberry. They are a classic design. Sterling silver ear wires.