You've made a really imaginative prop. I lived in south Florida for 17 years and clay is almost nonexistent. Now I've lived in mid-Georgia for 21 years and believe me I've slipped and fallen in clay all too many times. You are welcome to "harvest" as much as you want from around here!
We're close enough to Georgia that we get some clay streaks. But the poor Watcher has been living under plastic for most of the summer--we've been raining EVERY DAY!! (Yep--for six weeks. Kinda getting over it). I've sprayed sealer on him but don't trust it that much.