what you're looking for are soapstone tables- they're super cool! A lot of schools threw them out in the past decade or so because soapstone can contain asbestos. Well, what we call "soapstone" at least. It's not really a big deal unless you're grinding down the table or generating dust, but you know... people worry.

They're super cool though, I always keep my eyes peeled as well. I've definitely seen a few at construction junction over the years.