Granite under your amp???

Please keep in mind that granite does not have very good tensile strength and needs to be supported by something that has the ability to carry the weight and not bend. I was carrying a piece the other day by the edge and half of it just broke off and fell. Consider what would have happened if it was being used to support an amp. Ouch!

Does somewhere like Home Depot carry these? How much would I expect to pay?

What exactly does it perform? (Reducing vibration...?)

As for support, I would place it on one of my shelves on my Sanus stand.

Surface plates (the cheap ones I mentioned) dont' come as thin as 1", 2-3" is the norm. Shipping weight on the 18x24x3 is 200-250lbs IIRC. 17x19 (weird size, btw...not going to find something like that off the shelf) x 1 is still going to be 50+ lbs., at least. It's tough to estimate the density of stone until you work with it in person. For the surface plates I mentioned, $45-135.
-Ed

Anybody tried this one?

http://www.tnt-audio.com/clinica/sblocks1e.html

KP

I bought a piece of scrap granite from the neighborhood tomb stone guy.It is ~16"x18"x2" 50-60lbs.Shiny smooth on one side,dull smooth on the other.I paid $20, wiped the bird doo off it and painted it black.
I have a diy amp stand under the granite.In between the stand and granite is a very thin sheet of foam like material I picked up at a hobby shop.
My Pass Labs Aleph-3 sits on the granite.I still have the stock Pass footers under the 3.They are pretty good for stock.
Since using the granite the bass is tighter and a bit deeper.Focus is a tad better too.No doubt worth the money and effort.