I've used glass vials in a few of my paperweight designs.  I've also recommended them to customers who have asked for my help with items that needed to be "contained" before they could be displayed in a paperweight.  These have included tiny stones, minerals, soil taken from special locations.

This particular design is centered around a glass vial filled with crystal glitter.  There's a silver bail attached to the cork that seals the vial.  Through this, a length of thin twine was looped and tied with a small key and a paper tag that reads, "Emma's Star Dust."

There are so many different variations of this design that can be achieved by changing the contents of the vial, the text on the tag, etc.  A few that come to mind are wishes, dreams, fairy dust, and potions.