1) Does a small copper spot on a modern chinese coin affect coin value (i.e., resale value)and if so, by what percentage? Let's assume this spot is not distracting and a loupe is needed to appreciate it.
A high resolution photo can pickup any spot however tiny it is, and yes, I think it will affect resale value. How much? I don't know. It all depends on how you sell the coin and who your buyer is.
2) Do coins with and without copper spots get the same grade from grading companies, all other coin factors being equal?
I don't believe there are 2 coins being equal. I think in the lower end, they will get the same grade. In the upper end, they may not get the same grade. I guess people prefer MS70 coin to have no copper spots, or whatever other spots it is.
3) Do you worry about buying coins with copper spots? Is this something you shy away from, of do ou look at it as an opp. to get a coin you want for, possibly, cheaper?
Yes, I do worry a lot about copper spots. I don't want a coin with copper spots even it maybe cheaper.
These are opinions only, and I am no expert.
