My son picked up this rock after the tiller spit it out of the garden. He could not believe how heavy it is so he brought it to me. I tried to scratch it with a file and no luck there. Did an SG test on it and it came out a whopping 6.97. Streak test was brown to black.
I dug into my book and the only thing close is uraninite because everything else that heavy is way softer, not over three. There is/was a uraninite mine in Lusk Wyoming but I have not researched it. I may be able to get close to a Geiger counter at the college here because they have a large Geology department.
As far as safety goes all I could find was don't eat it, don't breathe it and wash your hands after handling it. I offered to try an X-ray on the grand kids but parents are so damn protective now days.
Any additional info on this would be appreciated.
Jim
It has the greasy look on old surfaces like they described also.
