Errors increase the value of collectibles because a limited number go into circulation before it is spotted and corrected.

A manufacturing error on the 1999 Georgia state quarter has increased the coin’s value, and some collectors are paying as much as $10,000 for the affected 25-cent pieces.

These eight quarters may look like just pocket change. But in the right hands, they could be exchanged for a fortune.

When that coin crossed the auction block, it realized $15,862.50, a figure that has since become shorthand among collectors for how extreme mint errors can rewrite the value of a modern quarter. The ...

Once known as the “Hobby of the Kings,” coin collecting is a global pastime open to anyone with an appetite for accumulation.