What is the perferred material for a TT shelf?

I have a DIY rack from three 3 1/2 in butcher block. The block is manufactured by patching together about 60-80 squares of maple with the grain running in different directions. My thinking, if you can call it that, is that the different orientations would preclude linearity in the wood thus reducing vibrations. I ran threaded brass rod capped with acorn nuts on each end. It sits on Herbies isolation footers. Seems to work great. 

I went with a 1.125" of solid cherry, Definite improvement over what I had.

Get a used Symposium Ultra on Audiogon for best sound.

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.