Okay folks, I'm stumped so I'm coming to the experts. This was toning out in the quarter range. Approximately 6" down. It has the look of stone,almost coal like. I can see specs the shine. It was pretty close to where I found the gold coin.
Well I live near many colonial iron blast furnaces and come across all sorts of slag ... And I have had it register as low as iron and as high as silver ... And have seen it in every kinda texture and form. Generally light weight.