Jewelry manufacturers in the United States must inform the consumer about precious metal content, but the content doesn’t actually have to be stamped on the piece. It can be on the appraisal accompanying the item, on a hangtag or packaging component, or on the invoice or receipt for the purchase. If a pendant is sold without a chain, it may not have a stamp of metal. If an earring is sold without a back it may not have a stamp of metal. The chain and the earring back have the stamp of metal.