A Tombstone in the Living room????

I have read that granite is awesome to put under electronics.Ive also read how very expensive it is.I went to our friendly neighborhood tombstone maker and asked if he could sell me some.(yes he asked what I wanted it for) I hate that! anyway he showed me some "pet markers" 18"x 12"x2" at $120 !! Then he remembered he had a scrap piece.(polished on 1 side)30"x 18"x 3" he said I could it have for $20!! He offered to cut it for $10 so I can end up with 2 pieces 15"x 18"x3" for $30 anyway,has anyone used granite under their components and how did it work out?