That stand looks nice with that slab on it.
Granite has long been standard for inspection tables where precision surface and vibration isolation is required. I have no doubt that other stones have properties desired for audio applications. My defunct TT prodject was to use a granite plinth. You might find a local granite counter-top shop that can hook you up inexpensively. They throw away tons of scrap that can be used, and often they will cut and polish cheap.
Granite has long been standard for inspection tables where precision surface and vibration isolation is required. I have no doubt that other stones have properties desired for audio applications. My defunct TT prodject was to use a granite plinth. You might find a local granite counter-top shop that can hook you up inexpensively. They throw away tons of scrap that can be used, and often they will cut and polish cheap.