I can see how it could be zen ... kinda like PDOoodling
lol. Just kidding! I do see how a repetitive action like that could be ... soothing. But 50 - 60 gross is a bit much, unless you have months and months to do it.
I know that doing ones own stoning is a great way to get costumes on a budget, though. Buy a plain dress and stone it yourself. I guess it works, if you have the patience.