Awasome Black Light Test For Cut Glass Ideas. Web so test your glasses with the test pictures at the beginning of this article. Web dealers and collectors who authenticate antique glass are grateful for the phenomenon that turns clear glass yellow under a long wave black ultraviolet light;
This will help you to get a better idea of its overall appearance. Crystal is heavier hold the piece in your hand, testing its weight. If you see a black square at the first image then your glasses block all blue light.