I think I have found my comparison stone for banded agate. It is 12.2oz , 5" widest point, 1 1/2 " Height at center:
I almost fell over when I googled Banded Agate and a picture popped up that had almost the same characteristics as this one. I have my fingers crossed that I am right. It will make sorting a great deal easier. From this piece, I can use my books to start to identify (or at least guess more accurately) the contents of intimidating boxes.
Any help or direction would be greatly appreciated!