In article , Joseph Gwinn wrote:

Aluminum is the most common metallic element on earth, and is about 9%
of the mass of the planet. There is more aluminum on earth than living
things. If it causes us any real trouble after all these aeons, then
there is no hope.

http://www.enotes.com/earth-science/aluminum

Absolute nonsense. Read the article you cited: it's talking about the *crust*,
not the planet as a whole -- which has an iron core. (Remember 7th grade
science class?)