It's a Liberty dime from 1942. These were minted from 1916 until 1945, and are also called Mercury dimes because people assume that's Mercury on the head--actually it's Lady Liberty wearing a winged cap. Could have fooled me, Lady Liberty.
You can read more about Liberty dimes here, if you're nerdy enough.
Imagine all the people who've had this dime in their pockets or change purses over the years. Imagine the very first person to hold this penny back in 1942. Back in 1942, the United States was involved in WWII. My late Grandpa Thames was a radio operator on bomber planes in WWII. Kind of a special dime, huh?