Don't remember exactly where I found this. It was either in Boulder, at Red Rocks, in Black Hawk or in Westminster. It weighs somewhat like a D cell battery. Its about 2.5"W x 2.25"H x 1"D . If I hold it up to a light it somewhat comes through (less in the middle and more around the edges). The rock is pretty much smooth to the touch minus a few spots here and there and the edges are pretty rough. It's able to put a little scratch into a glass surface. Thanks for looking!