Wow these are awesome and come in a set of 3! We have other colors and styles up now too! These would have been used in Victorian houses putting up small items / pictures. You would gently twist them into the picture railing until secure. Then the picture would be secured to a lovely piece of cord, or fabric, or ribbon and then hung on one of these; a really cool find. Note the pressed glass design, and the roughness around the edges. These across the top are about the size of a dime.

These were made by HEIDT Glass Co. N.Y. and recovered from their warehouse. HEIDT also used to make pressed glass for Tiffany Studios.