In all likelihood, you have a penny that has been plated with silver, pewter, or mercury. Countless U.S. pennies have been altered in appearance with the application of silver-colored (as well as gold-colored) metals. Edit: These typically have no numismatic value such as you cant send the coin in to be graded even if its in great shape, but value can happen in a couple cases like it was a collectible set or some other special release by a 3rd party that later was discontinued causing some demand to collect them. Whenever there is more demand than supply for anything the price can go up.
Whether done as a science experiment in school or purely for the sake of novelty, plating pennies has long been a popular thing to do — especially for those who have no numismatic interest in coins and are unaware that plating coins is considered post-mint damage (or PMD
), which can actually lessen the value of a coin.
You can tell if a coin has been plated by weighing it: If your penny was made after 1982 and it weighs greater than 2.5 grams, it was likely plated. https://coins.thefuntimesguide.com/silver-penny/
But as mentioned in the article, there are other reasons for the color that are unlikely here but you can read about them, and its always good to post photos when you can to confirm the suggestions.