Ha! Yeah... that was my first thought too. After I thought about it for a while, I decided that it might be better to find a masonry saw and start cutting slices off of it.
I did drop the big one on the way down the hill and a piece that was about 5 inches long, 3 inches wide and a half an inch thick broke off. The metal detector did not react to that piece at all.
Also... These things weigh at least double what you would expect them too based on their size. Everyone that picked them up was really surprised about the weight.
I have a call in to the geology professor at the local university to have him take a look at them before I start cutting but my curiosity is rising. I suppose I could start looking for a masonry saw while I am waiting for the call back.
-Mike-