To identify antique collectible marbles, study the colors and patterns of your marbles to determine their types, measure their sizes using a caliper, and use circle templates to check if the marbles are handmade or manufactured by machines. Read marble identification books by marble collection experts, and research about the distinct marble-making processes of varying manufacturers, especially Akron Agate Co. and Marble King. Marbles created during the 50s and earlier have good values.
Check if your marbles are antique and handmade by looking for a rough spot called a pontil, which is the area of the sphere's separation from the glass cane. Focus your collection on a particular element, such as German marbles made during the 19th century, for easier identification of specific marble characteristics.
Familiarize yourself with key terms in marble collection. Clambroth marbles made in Germany during the 1800s feature milk glass with outer twirls. Rare marbles have a black and blue base glass. Handmade marbles with oval, colored flakes on the surface are also worthy collectibles.
Machine-made marbles usually feature ceramic and glass materials crafted from machines, while contemporary marbles are created by modern glass artists. To immerse yourself in the marble collection culture, visit marble collector shows, see museums displaying marble collections, be a member of marble collector communities, and go to websites and forums where marble makers and collectors share information.