How rare is gold?

If you gather together all the gold mined in recorded history, melt it down, and pour it into one giant cube, it would measure only about 18 yards across! Thats all the gold that exists above ground now, or since man learned to extract it from the earth. All of it can fit into one block the size of a single house. Its weight, 91,000 tons- less than the amount of steel made around the world in an hour. Thats rare!