Recognize this mark?

by Steve Pearsall
(Hampstead, NH, USA)

I found this gold chain while metal detecting on a farm in New Hampshire (USA). The farm was first settled in 1720 and I have found coins from the 1720's and later on the site.

I found this chain recently. It was 10 inches deep which is usually indicative of the object having been in the ground for a considerable number of years.

Each link in the chain has this same mark on it. I have attached a picture showing one link which has some identifiable marks including the letter "A".

Thanks in advance for anything you can tell be about it!