Granite vs Wood DIY Audio Racks?

I recently upgraded my CDP which requires a bit more room than my current rack has to offer. While there are quite a few new racks I like, I find them to be a bit pricey so I figured I'd give DIY a shot.

The materials I'd like to use are either John Boos maple cutting boards (stained black) or granite slabs (black) which I can aquire at a local marble shop. While I prefer the granite looks wise, I rather choose the material which would sound better. Supports would be 1" threaded rod. Does anyone know where I can get 1" female threaded cones for the rods?

My listening room is on the 2nd floor and has an oak wood floor.

I appreciate any thoughts or recommendations.

Regards,
Steve