granites properties and splitting

What's the average weight per cubic foot of Granite (http://tanbrown.org) ?
Also, how would one go about splitting up an existing piece of Granite (http://tanbrown.org) roughly 6' long by 2' wide by 1' thick? Could I do this by hand (http://maplered.com) with a Stone (http://g603.net) hammer and (http://maplered.com) chisel? I would like to cut it in half length-wise, then cut each piece's thickness in half.