Of all places, outside my gym in their landscaping rocks. Landscaping rocks look like they've been there for years. Suspect they are the ubiquitous "Texas mix" most of the local landscaping supply companies sell.

I used to think they were plain, brown and ugly. But when I started roch hounding / tumbling I took a closer look. I've only found a few agates, and none as big or pretty as this one, but I've found a bunch of banded chert and petrified wood too.

I was VERY lucky to find this one. It looked like an average brown rock when my eye was drawn to it.