Please correct me if I'm wrong,
But the last person I knew who regularly worked his own claim on the American river, CA. told me a local firm who bought raw gold (not jewelry, PC, etc.) required a minimum of 2.oz sample to properly assay - BEFORE buying any. Plus, it's not their job to extract useful ore, that's your job. It seems in your case you'd have to crush that pretty specimen to extract the gold ore in order to assay it. Copper rounds are going for around U.S. $1.75 each. AU bullion around U.S. $1,780 today. So trying to extract bullion content would ruin your specimen. Might try contacting the local gem & mineral society to see if they could give you a lead on a buyer for the rock as is. If you're out West, there might be a local or University museum that might take it as a specimen donation for display (You can see raw gold as specimens from Great Falls, MD. in the "Hall of Minerals" in the Smithsonian Museum of Natural History!) - then they could give you a receipt for tax deduction purposes. FWIW
