On a crystal wine glass, for instance, look for a thinner rim with less of a lip. [1] X Research source
For example, a normal drinking glass will make a liquid inside it appear cloudy. Crystal glasses, on the other hand, provide a greater view of the liquid.
Lead-free crystal feels lighter and more durable but still shines when held up to the light. [5] X Research source
Wet your finger and rub it around the object’s rim, if possible. Crystal will produce a musical tone, but glass won’t.