Mine are primarily gold and sterling, many dating back to Civil War era or earlier, but almost every other material they were made from. Storing is a problem, tho they need so little space. I also collected other sewing smalls..measuring tapes, pin cushions,thimble minders. etc. So some are in thread cabinets, in glass cabinets, and even on walls in printer's trays. It's important to keep records of when you bought and amt you pd for your heirs, or they will end up in a shoe box in a yard sale!