A childhood belief about chemistry

When I was in grade school we did a project where we put different kinds of rocks and dirt in a jar with water and watch them settle out over time. My teach explained that this is how sedimentary rock is made. So, I thought, if I kept the jar long enough, I would eventually make my own rock. My dad explained that it would take more than my life time for this to happen. So, I planned to pass the jar down to my ancestors (great inheritance, huh?), until it became a rock. This grand plan was thwarted, though, when my sister bumped the shelf if was on and toppled the jar onto the floor. To my mom's and my dismay, it was just mud.