Lalique Crystal~Glass was founded as a jewelry company by Rene Lalique in 1881, and became known during the Art Nouveau period for its lead-based glass vases, bowls, and decanters with enameled or acid-etched...
Do a lot of research before buying. Read antiques and collectibles books (there's also a lot of information on the Web). Bone up on history, which often gives clues to why things were made the way they were...