Hello! I am new to this forum and new to the world of identifying rocks and fossils. I have several rocks and fossils that I am trying to identify on my own, but this one is proving to be beyond my VERY limited knowledge. My grandfather and I would go rock hunting in the Texas hill country when I was a little girl. He recently passed away and I am now slowly moving all of his rocks that he collected throughout his life to my home. Unfortunately, I do not know much about this rock. I ASSUME he acquired it in the Texas hill country but I am not certain. The rock is VERY heavy, especially fo