Recycling marble

Could you build a (really solid - bricks?) base for it and use it as a garden table? Or incorporate it into a water feature, maybe propped up at 45 degrees with water cascading down over it into a pool? Or fix it standing upright, partly buried, as garden sculpture?

It sounds too good to waste. If you can't use it at all, you could advertise it on Gumtree (charging something) or Freecycle (free) emphasising that it is "buyer collects". Someone will have a good use for it.

Buy a column from a garden centre and use that as a base

Can you get a hole drilled in the centre? I have an old mill stone and I have a water feature made of it, the water just trickles down from the central hole into a little pit below, then is recycled round and round with a pump. I've propped it up at the back with cobbles, but you could maybe have it against a wall?