Yeah that law is ridiculous. What happens if you are a metal-detecting enthusiast looking for valuables and you stumble upon something archaeological? Are you just gonna get fined?
Most things of value are going to be archeological. If you want gold you do panning.
https://www.smithsonianmag.com/smart-news/amateur-treasure-h...
And would likely be considered important archeologically.
TL;DR finds of over 2 grams have to be given to the state (you might get it back).