DetectingWales.com

I found this a few months ago and though some of you would like to see it. When I first saw this coin at the time of finding it my heart nearly stopped, as the silvering was quite strong in the natural light and I thought the green was just from the earth rather than it being a copper alloy coin. Finding a real Halfcrown of William III would have made my day, but sadly it is Contemporary Forgery, dated 1697, but I am still pleased with it. In actual fact it's the silvering that has saved this coin from deteriorating further. And although it's a forgery, I find the detail they went to, to make this coin, is unbelievable!

and the detail is actually better than most of the real ones ;D

still a nice find, well done m8  ;)

There must have been a gang of forgers around at the time, I found this crown in the Kington area  also a contemporary forgery, although not in as good condition as yours. It has no sign of silvering and is too worn to date. It must have been in circulation for some time or a copy was taken from a worn coin.
The weight is also wrong being much lighter. I would have thought that wouldnt have fooled anybody used to handling these coins on a regular basis. 

Excellent find Jon well done mate. It still has the same historical significance as the real thing and as I've said a few times before,  to me, a lot more interest considering the sentence if you were caught making them. It came under the offence of High Treason, which carried the death penalty (men by being hung, drawn and quartered and women by burning,) the last women to be burnt at the stake (after being hung, more humane ???) wasn't until 1789, and the last hanging for forgery wan't until 1829.
A young woman was hung at Newgate in 1819 for "passing counterfeit coin" and not actually making it, so it shows that the profits must have been great to risk all.