Necklaces that let you add charms inside a see-through case are called floating lockets or living memory lockets. How Floating Living Memory Lockets Work... Design: They feature a pendant made of a clear glass or transparent crystal face with a metal frame (often stainless steel or alloy). Closure: They use a secure magnetic or screw-top clasp so you can open and close the case easily. Customization: You place tiny miniature charms, birthstones, or letters inside the transparent space so they look like they are floating. Flexibility: You can open the locket anytime to swap, add, or remove charms to match your outfit or tell a personal story