anyone care to explain to me what pitting is exactly please or what it even looks like? and how much would it affect the value of a 500 dollar coin in g4?
You probably have a better chance of getting your questions answered if you make your thread titles a lot more specific, so people know what you're asking.
Pitting means the coin has suffered from corrosion. How it would affect the value of a $500 coin in G4 would depend on how extensive and how severe the pitting is. In either case it will reduce the value. Only question is how much. Without seeing the coin the question is impossible to answer.