The best material for a platform for floorstander

.......I have a concrete floor with Berber carpeting ...not too thick with pad maybe 1/2'' total.... In an effort to get them off of the floor as it is a basement, the room is temperature controlled ... the spikes on the speaker do raise them about 1/2 '' to 3/4'' from the carpeting and the spikes I am pretty sure are anchored on the concrete......just to get them as I said ; '' off of the floor '' - any ideas ?
Granite slab that you can order at the monument shop. (they'll be glad to do job for living perhaps with good discounts :-))
I wouldn't sweat it as long as speakers are elevated...I'm sure others are going to mention Italian marble, spikes made from rhino horn, and 6ft bamboo stilts... Don't bite