The earliest paperweights were made in the 1840s in Venice and were made out of glass cane and crystal scraps formulated into a cylindrical shape. The art increased in sophistication and technique, with French paperweight makers including small flowers that appear to be suspended inside the paperweight and delicate, intersecting glass patterns. Some of the most famous makers of paperweights included Baccarat, St. Louis Company and Clichy. Many paperweight manufacturers placed labels on the bottom of the paperweights, which can be useful in identifying information about the paperweight.
Turn the paperweight over and look for the paper or foil label. Many paperweights are missing the label and are not marked. If a label is present, most identify the manufacturing company's name or location where the paperweight was made.
Visit your local bookstore or library to learn more information about antique paperweights and labels. Examples of reference books include "Collectors' Paperweights: Price Guide and Catalogue" by Lawrence H. Selman and "Paperweights for Collectors -- an Illustrated History and Identification Guide for Antique and Modern Paperweights" by Lawrence H. Selman and Linda Pope-Selman.
View online galleries of paperweight manufacturers once you have the name of the company that made the paperweight. Be sure to look at photographs and pricing information. One such website is Replacements.com. Click on "Collectibles" on the main page and then the first letter of the paperweight company's name, such as "B" for Baccarat. Click on the identifying link, such as "Baccarat -- Paperweight" to view piece names, patterns and pricing information.
Search online auction websites such as eBay.com or Bonanzle.com with the information from the label to find similar items and view current market demand and value for the paperweight. On the main page of the website, do a search with the exact information listed on the paperweight label and scroll through the listings that contain similar content to learn more information.
Visit antique stores and collector shows and bring the paperweight with you to request identification assistance from dealers if you are still in doubt about the paperweight's origin. Call ahead and ask if the dealer is familiar with vintage paperweights and if they can refer you to other experts in the area.