However, in the late '80s, they came back in a big way as a collectible, he says. A lot of the interest was nostalgic, but many collectors also consider marbles works of art. "A lot of the early glass ones are especially beautiful."

Another thing that's nice, says Jackman, is that marbles are widely available. Plus, most are fairly inexpensive.

You can get handmade clay marbles from the 1880s for about $2 apiece, he says. Marbles known as Benningtons, clay marbles with a glazed surface that looks kind of like pottery, can range in price from about $2 to $25. "They were made from the late 1890s to about the 1920s. With Benningtons, the value depends on size — bigger is better — and on whether there's any green or blue in the glaze. Those are more rare."

Glass marbles became more widely available in the '30s. "They are really collectible," says Jackman. "They have such vibrant colors and come in so many variations it can be mind boggling."

These glass marbles comes in a variety of styles and patterns, including swirl, ribbon, clambroth, peppermint swirl, mellonball, lutz and others.

Handmade glass marbles from Germany are especially prized, he says, although others are also sought-after. China also produced some early marbles.

You can tell when marbles are handmade because they have what is called a "pontil" mark — the mark made by striking the marble and separating it from the end of the rod.

Glass marbles made by machine began appearing in the late 1800s. In the United States, Akron, Ohio, was the largest center of marble manufacturing. Between 1884 and the mid-1940s, some 30 marble factories were located in Akron.

Among the more famous was the Akro Agate Co. "Akro agates are very nice," says Jackman.

Other well-known manufacturers include the Dyke company, Christensens, Peltier and the American Marble & Toy Co.

One unusual kind of marble is the sulphide — a clear marble with a figure inside. "Animals were the most common figures," says Jackman. "Numbers and people were also used. The people are really rare. If you can find an original one of those, it would sell for hundreds, even thousands of dollars."

Peltier also made unusual marbles, including some with comic figures. "Originals of those go for around $250," says Jackman.

But, he notes, a lot of the old designs are now being reproduced. As with any antiques, "you really have to know what you are looking for. Some of the new ones look like the old ones, but the patterns are just wrong. It's like finding a '57 Chevy and you think it is perfect, until you realize that the front is a Buick. It's easy to get duped."