Here is a jar of 7 pounds of very dense black sands I've saved from panning the ancient glacial moraine. I find tiny gold flakes in ever pan, but there's also a fair amount of this incredibly dense sand which is quite hard to separate from the flakes, even when its particles are smaller than the gold. I have managed to crush a tiny amount and find 'flour gold' inside some of it, I even managed to have a lucky find of a quartz stone with a hematite grain cracked in half on the surface and a little speck of gold shining inside. So I this will at least be worth a test smelt to see what the PM content is! Still have a long way to go with that, as I need to finish building my furnace and get the remaining tools I need for smelting properly.