Thanks for the compliment QM....my son is 11 years old so I don't know how appropriate his Science fair project will be but I believe it is something that will make someone think...especially with the speciman I have that is as big as the egg of a Robin...
I put my stones in water and the dark green ones are slowly turning to a lighter green and the water is turning green as well....hopefully they will still be a good demonstration since the fair is not til next Monday.