Hi there, I just want to make a radioactivity detector to see if some minerals are radiaoctive or not, I want it to be as cheap as possible, it doesn't have to be too accurate, just for detecting if some ores contain significant ammounts of radioactive metals.

Any ideas?, I found a very cheap one here:http://madscientisthut.com/wordpress/ but I have to be moving so I don't know if it would broke or something like that.

You can use the same principle as in the link (I don't see any obvious errors with it) and simply make a more sturdy version.