Antique marbles are collected the world over, with rare examples traded for thousands of dollars. Early, handmade examples produced in Germany are particularly sought after. Following the outbreak of World War I, sales of American machine-made marbles grew as German exports were banned. Millions of marbles with thousands of different patterns were produced, providing ample scope for the enthusiast to start a collection. Being able to identify rare, antique marbles, both handmade and machine produced, can help you place a value on a prospective purchase.
Hold the marble in your hand and rub your fingers over it. If you can feel two points opposite each other, then your marble was probably handmade and is sought after by collectors. These marks are called pontil marks and were created when the glassmaker cut the glass rod from which the marble was made.
Look at the center design. Rare marbles have small, white figures of people or animals in their center and are very collectible. First produced in Germany beginning in 1840, these marbles are known as “sulphides” and are usually 1 1/14-inches big.
Compare the color of an antique marble to that of a modern one. Early marbles have much more vibrant colors than their modern equivalents. If color was applied to the surface over a clear glass base, the marble was likely made after World War II and isn't as rare as earlier examples.
Visit a marble museum and study its collections. This will help you learn how rare, antique marbles look and recognize different patterns. You can also join a marble club and attend meetings to discuss all aspects of marble collecting.