Here in America, many states have antiquities laws foisted upon us by archaeologists' influencd lawmakers who have placed a cut-off time limit for finds, after that length of time, the find becomes property of the state without any "finders' fee".
My state, NC, has set that limit at 100 years. If an item is or believed to be 101 years old or more, it is the state's.
Here in the rural West where most land is Federal land controlled by the Bureau of Land Management (BLM), anything over 50 years-old is a relic. So if I threw an empty Coke bottle out into the desert from the window of my Dad's Buick back in 1960, I could now be arrested for going back to pick it up.
In Virginia if you dig it up on your own land it is yours, period. Sadly..that even includes GRAVES found on your land..they become YOUR PROPERTY. I know this because one was pillaged by the “church” who bought a portion of our family’s land. I assumed a church would keep in intact and had feared a developer would destroy it. Well, the church dug up the bodies and hauled them away and kept the Civil War era hand carved headstones. I tried for 3 yrs to do anything about it to be told...Sorry...they bought everything and anything when they bought that land.
Oh well....