“...the government buys it from you at a price that they determine.”
...so at about 10% value would be my guess. Then they tax the sh** out of that.
That’s a bad enough deal to make a detectorist expectorate.
Actually, they are required to buy at market prices, as determined by a committee composed of surprisingly representative people.
The purpose is to make it so that people WANT to report finds, not just forced to.