I found one (1''x1.5'') out in the middle of a field that has a 300 year old oak on it's border. It not being native to the Finger Lakes, I could only assume that it was passed and traded among many of the First Nation till it ended up in a Seneca's hands and was lost in the crop field they were tending. An adjoining field has given me numerous arrow heads and one pottery shard that an 'expert' had said was from a 'Sacred Corn Pollen' pot. Also this adjoining field has given up more then 40 col.buttons and 20 col coins and assorted artifacts! (now privately owned and no longer farmed) After finding a lost tractor part for the farmer, he gave me permission to hunt the area which has a basement that does not show on any of my maps, going back to 1850. The newest coin was an 1818large cent in EXCELLENT CONDITION! (the oldest, George Ⅱ) This area is on the Sullivan Trail, which would have been a main road some 235 years ago.
back to the copper- yes, it was green----I keep it in my change pocket till it polished bright, lost it and found again on my lawn ten years after the fact!! (it's now in my 'traveling museum)---
ps, click on image to make it bigger----