I'm no expert (really on anything) but I've learned a few tips for determining crystal vs. glass--in general, if you flick crystal with your finger it will make that musical "ping" sound, whereas glass will make more of a dull thud. Glass often has seams to it (a line you can feel extruding from the piece) and not crystal; also, crystal will cast a rainbow "prism" glow if you shine light through it, whereas glass will usually just reflect the light straight. Also take a magnifying glass and study the piece for any numbers, logos, or markings that can help you identify the piece. There are a lot of great websites out there that have photos and identification for the markings on glassware, ceramics, crystal, china, etc.