Native americum 241?
The source referenced for nuclear bricks only indicates that americum 241 is a biproduct of nuclear reactors. There is nothing about any possibility of producing americum 242 from potential native americum 241 on Mars.--Farred 03:18, 22 February 2010 (UTC)
According to the Wikipedia article on Americium there are no isotopes of Americium with half lives greater than hundreds of years. This precludes there being any native source of this element on Earth or Mars. It is completely an artificial element.--Farred 03:32, 22 February 2010 (UTC)