They can be rare. They’re often difficult to spot. But error coins are certainly out there. And if collectors know what to look for, they might just come across a number of unique pieces with relatively little effort.  While such coins can demand a price premium, they offer hobbyists with a chance to procure one-of-a-kind pieces for their collection.

Before you start scouring through you change jar for errors, it’s critical to know what types of common error coins are out there. While just about any error could occur during the minting process, here are a few well-traveled errors that could show up on coins:

Double-dies: Just as the name suggests, double-die errors occur when a coin has been pressed twice during the minting process. In turn, the coin receives a second, misaligned impression of the die. These re-punched coins leave the piece with what looks like a 3-D perspective. A well-known example of this phenomenon can be found on the 1955 Lincoln penny that suffered a doubled-die error.

Broadstike: This is an error variation that occurs when a coin is struck without a collar. In these instances, the coin may appear off-center, or may have features that include what appears to be an overly-thick rim around the edge. A broadstrike is not an uncommon error in the U.S. minting process and can be found in every denomination of coin.

Missing features – While it sounds hard to believe, the U.S. Mint has been guilty of omitting central characteristics from its coins on occasion. In a notable, recent example, certain Presidential Dollars that made it into circulation lacked the edge lettering intended as part of the design. The error was found on George Washington and John Adams versions of the coin. In addition, the Adams coins were also found to contain doubled edge lettering in some instances.

Superfluous features – One of these errors made headlines a few years back when it was discovered that Wisconsin variations of the State Quarters series contained extra high and low leaves due to a strike error at the Mint. Lesser-publicized errors were also found in the series – likely due in part to the intricate designs of the coins – such as the Minnesota extra-tree errors that surfaced. In all, some 60 errors are known to exist on the coin honoring the Land of 10,000 Lakes.

Another Father’s Day has come and gone, but the holiday always leaves me feeling a bit nostalgic when it comes to coins. It was during my youth that I was introduced to the hobby by a grandfather who still has a special place in my heart. Though he’s been gone for some time, the passion for collecting that he instilled in me back then remains strong. And it’s one that I hope to pass on to my son. Even though he’s still young, I’ve already planted the seeds to get him curious about coins and how much fun it can be to hunt them down.

Though Father’s Day has passed, I wanted to use this opportunity to make a coin-related plea to all the dads and grandpas out there. If collecting has ever been a part your experience over the years, make sure to get the kids in your life involved in the pursuit as well. Everybody needs a hobby growing up and, frankly, I can’t think of a better way to spend time with a child as part of a simple and fun activity.

It doesn’t take anything complicated. All you need is a pocketful of change to strike up the conversation. From there, you can build on a child’s interest and introduce them to rudimentary tools of the trade, from providing them with a National Parks Quarters map or by giving them a few coin folders, the traditional hallmark of many budding collections.

If it’s clear that they have an interest in coins, build on those first steps by simply picking up a few rolls of Lincoln pennies or State Quarters to introduce them to the thrill of finding missing dates in their folders. Or if you’re convinced that the child will take to the hobby for the long haul, go the extra step and gift them something like a membership to the Presidential $1 Coin Club or the National Parks Quarters Coin Club to keep that momentum building.

No matter how you choose to get kids involved, make sure to do your best and pass on all you know about coin collecting to the next generation. While this year’s round of Father’s Day presents may be unwrapped, it’s never too late to teach kids about how much fun coin collecting can be. It’s a gift that will surely last them a lifetime!