Design Extensions Puzzle Variety Experts

Leading variety coin experts have been puzzled for several years by a type of minting process error called "design extension." Design extension, an example of which is pictured here, appears in the form of "trails" that extend from design elements on the subject coin. This phenomenon has also been called "die trails" and is often found on pennies that exhibit "wavy steps." (Wavy steps are seen on Lincoln Memorial Cents; sometimes the steps don't appear straight like they should, but sort of wavy instead.) Some experts think that the die trails are a form of doubled die, while others think the cause is different (but they're not sure what that cause is yet.) Everyone agrees that the die hubbing process is the source of the distortion; something goes wrong when the working die is created from the hub.

Until recently, the design extension phenomenon was only confirmed to exist on U.S. coins. The first types to be identified were on Lincoln Cents, but now the die trails have been seen on all U.S. coin types currently in production. Over this past weekend, the first non-U.S. coin exhibiting die trails has been confirmed: a 1953 Canadian Nickel has been found with design extension marks on it!

Variety experts BJ Neff and Robert Piazza have created a Web site called TrailDies.com to catalog and investigate the design extension/die trails phenomenon. Since this phenomenon has been proven to occur at the die level (rather than the individual coin level), design extension coins represent a legitimate collectible variety akin to doubled dies, 3-legged buffaloes, and other similar die-based types. The day may soon be upon us when coins that exhibit strong die trails like the example shown here will be worth strong premiums in the collector market. If you're looking to get in ahead of the curve on the Next Big Thing, I think this variety type is an excellent bet!

• Learn more about Design Extension and TrailDies.com

Photo courtesy of BJ Neff and TrailDies.com