China identification is relatively easy, especially nowadays. Just turn it over and read what it says. Or, for older patterns, it is simple to explain what you have based on design, color, trim etc.
Not so crystal. To the average layman all crystal looks the same. Taller or shorter, wider or narrower, but the same nonetheless. Some patterns are unique and easily identifiable, see Edinburgh Thistle (cut) and St. Louis Chantilly. But what about the “regular” patterns, the ones that you can’t pick out of a lineup (Waterford Powerscourt and Lismore come to mind)? Diamond cut, wedge cut is not known or noticeable to most people and most glasses are colorless so how can it be determined which brand and pattern crystal you have?
In all honesty, you can’t (that’s why we’re here :)). The brand name is often etched underneath the glass, but that’s it. Pattern names are never inscribed and unless you have the original paperwork and stickers, you’re up the creek.
Your best bet is to take a few pictures: one of the glass in general and one a close-up of the cuts of the pattern and send it to a crystal company such as ours. It’s free and accurate so what do you have to lose?