We believe these earrings go back to the 1940s or earlier before there was much standard marks on silver jewelry in Mexico hence why it is only marked ?Silver?. We have noticed this on other pieces in the past. The screw back design also hints that way but no way to know for certain. Please note the odd design that if you wear earring pointing down, the deer is hanging upside down. Otherwise you have to screw them on the other way and have the deer sitting up which means it goes up your ear lobe. Funky. But we like finding funky. Will ship USPS with tracking to winning buyer