Hi! Fantastic thread! I'm still learning how to post pics so I might not be able to..but..I have a rusty quartz sample I found the other day that had a lot of black on it..the sample seemed unusually heavy. When I got home I started crushing it and to my surprise it broke open to expose a matalic silver material. Sparks came from the rock when I hit it with the hammer..kinda smelled like burnt gunpowder when it broke open.. I can pick up the black portions of the sample with a magnet, but the shiny portion was not magnetic. I tried scratching the shinny part with a screwbriver to no avail....I looked in a few of my rock books and everything with a silver shine should have been scratched with the screwdriver..this rock crushed hard..its not in cubic form and does not flake apart..after reading the description of arsenopyrite I heated the sample with mapp gas (outside) and low and behold it became magnetic,,and crumbled apart. When I pan the fine ground sample there is some kinda shiny stuff that is very very heavy but very very small. Does not shiny like gold but almost..hard to tell when it is ground so small..there is a small ammount of gold in the sample...any tests or suggestions would be great, thanks.