Marbles have been a toy since the 1800s and became collector's items starting in the 1940s. Vintage marbles were made by a variety of manufacturers in many different colors, patterns and styles. Around 1950, companies in Japan began to make cat-eye style marbles, which were so popular and inexpensive that most companies in the United States ceased making marbles. There are a few ways to identify authentic vintage marbles.
Look for glass marbles with swirls in a variety of colors with white threads through the swirls, which are indicative of German handmade marbles that were made somewhere between the 1850s and early 1900s. Other examples of German marbles from this time include black marbles with swirls, marbles with gold metallic swirls, and images of figures or animals, which are the most valuable.
Find clay or ceramic marbles that are white with designs painted on them or marbles that look like crockery in shades of blue or brown. These were also produced in Germany from the 1850s through the early 1900s.
Look for clay marbles with red or blue decorations, which are indicative of the first American marbles and considered the most valuable. However, be aware that these are frequently reproduced, so look for a rougher exterior with faded marks, as these are more likely to be authentic vintage marbles. If the marbles look brand new, they are less likely to be authentic.
Find glass marbles that are identical or nearly identical in size, shape and color. These are machine-produced marbles from the United States in the early 1920s through approximately 1970. Some of the companies that made glass marbles included Christensen Agate, Vitro Agate Co., Marble King and West Virginia Marbles.
Read reference books on marble collecting to view photos of vintage marbles and read detailed information about finding, identifying and collecting marbles. An example of a reference book is "Marble Collectors Handbook" by Robert S. Block.
Visit antique stores and marble shows to view vintage marbles. Speak with the dealers about vintage marbles and specific identifying characteristics. Meet and talk with other marble enthusiasts online and at shows about individual marbles and compare notes on how to find vintage items.