well , it's sort of Geiger Counter.
Well it won't measure density it measure the amount of Ionized particle that are emitted from the sample.
you can't unless test the sample in laboratory as far as I'm concerned that sample can be pure plutonium and you can't say it by looking at the device , the only thing that is sure is that the sample is emitting far more radioactive particle than I care to live beside the mine.
Geiger counter measures level of radio activity (Alpha Beta) and not the density of the Uranium as it is portrayed in the post with geiger meter. The thread is a misnomer with false input.
And do you know what the C and S stands on the instrument?