Yes it’s just a final smoothing cycle as I recall. There is no lacquer on the rocks. Thanks for all the helpful answers. I’m feeling pretty good about them, but there are a lot so I might just pour an inch of vinegar from the giant jug in the garage and see if any bubble...
In case anyone wants to play a game - here is the rest of ‘em, ignoring all the ordinary quartz and river rock. If there are any rock aficionados who want to tell me “Not THAT ONE!” 😄 I’ll likely not put all of them over the substrate but definitely the unique ones. Thanks everyone!