What is the perferred material for a TT shelf?

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Sand encased in a framed maple box with fixed bottom and floating top is my current method of vibration dampening experimentation. I made a few boxes of varying size settling on one with 6" total depth, subtract 1" for the piece of floating polished granite on which the TT sits upon leaving 5" of kiln dried sand, after allowing adequate time for some settling and an additional layer of sand. Naturally different TT and platform weights along with box depths/ capacities can vary results. Too much weight may over pack the sand causing it to be too uniform lessening its otherwise positive dampening properties. But I think I'm on the right tracks. I may have better results with a lighter piece of plywood or acrylic acting as the floater, and or a deeper sand box to play on.

As with most things having some variety to experiment and fine tune is never a bad Idea. Being accused a typical male as I'm sure many of us have at one point may of been what caused me to reach for the shiniest heaviest material I had in my arsenal knowing full well it may over do it. The lighter ply is still open for evaluation. I think I could live with current arrangement in comparison to some others below. But again I'm a guy so why would I not attempt fixing what isn't necessarily broken.   

I have tried others including steel target shelves, plys, blocks and air suspension made possible with the bike tubes and ingenuity. So far the sand case sounds pretty effective to me. Or the sand hasn't finished settling. After putting forth time and effort if results meet comparable to others the finished sandboxes look great so that brings with it a certain level of contentment. At least for a while.    

If it were me I'd use the roller bearing assembly type Isolators in conjunction with, I.e., on top of the sand filled boxes.  Should be a match made in Heaven given the sandbox is acting primarily in the vertical direction and the roller bearing assemblies act primarily in the horizontal and rotational directions.  

I like the direction williewonka takes but would experiment with the final grounding to the granite. His method does allow for easy checking on the isolation of the granite from vibration--just sprinkle salt or sugar on the granite and play your music. Cheers.. to the eyes...

I use to think granite was a good material, then switched to thick Maple blocks.  They sound much more natural, and still has the dynamics, and speed that granite provides.  So yes Maple is currently still my favorite material.  Obviously what ever your equipment sits on it takes on that character.  I have tried many different materials, carbon fiber, concrete, granite etc.. But wood just sound more natural, less harsh, yet still has good dynamics, speed, but just with a much more natural sound.  I would love to try other woods but the time and money to try them all lol