Recently I did a bit of web research about repairing lead crystal, and evidently it can be done.

Thank you, Frank, for the info on what adhesives to use. Have you any experience with the UV-cured adhesives?

And what about this glass repair epoxy:

http://www.amazon.com/PC-Products-PC-Clear-Adhesive-Syringe/dp/B008DZ19WC/

Good ol' Loctite glass glue works, too - I've used it for synthetic sapphire joins as well as glass.