Crystal glasses and other crystal dishes are often family heirlooms that are expensive to replace, so breaking one can be a disappointing loss. If your glass is not chipped or dangerous to drink from, you can attempt to glue it with a strong epoxy or a glue designed specifically for crystal. While it may never look exactly like new, the glass may keep your special set of glassware intact.
Examine the glass closely and look for any chips on the inside of the glass or near the lip. If there are chips in the parts that hold liquid, the glass may not be safe to drink from and you may have to discard it. Examine the glass even closer with a magnifying glass.
Wipe down the glass pieces with a glass cleaner to remove any oil or dirt. Do this carefully so that you don't cut yourself.
Lay down newspaper on the area where you will glue the broken glass.
Place a dot of epoxy, glass glue or crystal glue on the location that needs to be pieced back together. Press the pieces together. Wipe off any excess glue that sticks out from the sides of the jointed location. Hold tightly for at least two minutes or until the glue begins to set.
Place the glass in a position that will not put strain on the glued portion but will allow the glue to fully dry. If the cup portion was broken from the stem, for example, place the glass upside down to dry. Read the instructions on the glue for that particular brand's full drying time, and don't move the glass until that amount of time has passed.
If you have a major chip in the crystal, you may have to have the glass ground down by a specialist in crystal. Using a crystal grinder and polisher, it is possible to salvage your family heirloom.