Hello MechEs (or anybody else who'd care to reply) I'm about to get a small, but fairly sensitive analytical scales recently (down to 0.01 mg) and now I'm trying to figure out a way to dampen ambient vibration from the room and its surroundings (people walking around, HVAC, etc.) 

I've got a 200-lb slab of marble that I intend to put the scale on, and I plan to set the slab on a counter in a corner of the lab away from air drafts. I consulted one of the laser techs in the department who also suggested putting multiple vibration damping "pucks" between the slab and the counter. Apparently, they're neat to throw around because you can throw them really hard at the floor and they'll just land there without bouncing back. He's used them previously, but can't remember a brand name or supplier. 

Apparently, these are used to dampen speaker vibrations, and prevent transfer of roughing pump vibration to the floor. So has anybody ever used these before, and remember what they're called or where I can get these from? Better yet, does anybody have a better solution that isn't super expensive? (i.e. pneumatic supports, giant block of concrete, etc.)

Thank you!