I guess I was trying to say that native copper is soft and flexible. All my minerals are boxed up, so I can't send an image. A pin scratch will show copper red if that's what it ia.
Marbles refer to the loose mineral deposits which develop in a water heater. If your water heater rumbles, and shakes, you have marbles which act as boiling chips.
Here's the Bryan watch I mentioned a while back. I finally dug it out.
It is an 18 size incomplete duplex movement Knickerbocker (N.Y. Stanbdard) watch co (1890-1930)
As an aside, my maternal grandmother worked knocking on door for Bryan in Kansas.
It's hard to tell. It looks like a piece of native metal with some ?calcite inclusions. Try using a file on a small corner to see if it leaves a metallic surface. I have a chunk of native copper which has a similar appearance.