That's a lot of money right there he's planning on throwing away. If you don't want it, at least stick it on ebay with a reserve at say 50% of whatever it would cost to buy that size and shape. Lot's of online calculators where you can work out what that exact dimension would cost to buy. And a shiply quote to find out how much to deliver it.
Why would it no longer be useful, it's millions of years old, 10years in a kitchen isn't going to ruin it.