I found these 2 rocks while walking a spot in my backyard I wanted to mow, just look for anything that might give my mower fits. They seem to be sandstone in my opinion, but they have some odd markings, makes me think of petrified wood, but I figure that's wrong. So if anyone on the forum knows, I would like to know what they are. I just put them in my lava rock because I thought they were kinda cool.