Granite surface plate

It will ring like a bell and give you a bright treble balance .Try Symposium its neutral and will give better stage ,bass,midrange etc.

Bpoletti,
I would suggest that you call Adona. I am sure that they would sell you one of their granite shelves. They are the best of both worlds. They bond granite to a layer of MDF with a special (proprietary?) polymer. Anyway, it eliminates problems with ringing etc. Visit the Adona website. I have been using one of their racks for abourt 4 years and like it very much.

I use 3 x granite block samples as feet
for my
turntable. (They are about 4" x 4" x
1.5")
I decouple the plinth from the blocks
with
brass compression rings on their side.
See
my system pics. This way there is no
granite ringing but there is excellent
focus over butcher block.

I don't recommend this.
I have one from a machine shop and it really sounded bright and shrill.
I use a 3" thick maple block and I'm very happy with the warm clean sound wood brings to the table.

A simple way to dampen ringing is to apply a constrained layer damper onto the horizontal support surface/shelf.
The one I found to give excellent audible improvement is from Machina Dynamica: VibraBlock Constrained Layer Damper.

Responding to the mention above where brass compression springs have been used,
The same Machina Dynamica can supply "cryogenically treated high-performance hardened steel compression springs"
cleverly named "Cryo Baby Promethean Mini Isolators."

These may be placed against the rigid flat bottom of a component to support the component which is resting upon a horizontal surface. Whether this horizontal surface is granite or wood may be a matter of what sounds best; I prefer wood.

Next place the VibraBlock constrained layer damper onto your chosen shelf.
I prefer what I hear with this damper placed onto a supporting shelf for a component, rather then placing a damper directly on top of a component.