The law here in the UK is you have to report finds like that under the Treasure Act. Call your local finds liaison officer, they're used to this. They'll help get it recorded and valued, and a museum might buy it. You'd then split the reward with the landowner if that's not you. It feels wrong to just put it in a drawer, and doing it right is simpler than you think. I had a friend go through this and the process was very clear.