This new design was actually a suggestion from a customer (some of the best ideas start this way). I hope Maggie likes how it turned out!
The square is a thick (18g) piece of nickel silver with a copper heart securely soldered on. I can also do this tag in copper with a sterling silver heart. Now that I think about it... I could also do it in brass or bronze with either color of heart too! Just let me know how you would like it and I will make it happen.