Key Date Mercury Dime
Hunting a park that dates to the late 1800's I found a hot spot where I've been finding lots of Mercury dimes, a few Barber dimes and many wheat pennies from the teens and twenties, even an 1899 Canadian quarter.[split]
Well on a short hour lunch hunt I find a Mercury dime (could tell by the back) and put it in my pouch, not looking at the date.
When I got home that night I rinsed it under the water and saw the date 1921 and quickly checked the coin book because that date sounded familiar to me and sure enough it's a key date and in pretty good shape too.