What is the wood for the center island? And, can it be used for cooking prep?

The wood countertop is a sustainably harvested mahogany finished with Emmet's "Good Stuff" Wood Finish. It depends on what you mean by "cooking prep" as to what it can be used for. Cutting on the surface will (like any butcherblock top) damage the surface and compromise the finish. It is a hard wood and a durable finish, so it can be used like any other solid surface countertop.