In gratitude, they turn the flower he made for Arya into gold and other precious metals. LIVING metals, that will continue to grow.

Oh, dear. Tamora Pierce wrote about living metals in her series The Circle of Magic. In the third book of the series, Daja, a smith mage, accidentally makes a metal plant that grows by abosorbing minerals and new sources of metal.

This seems to be another one of Paolini's random details he includes just because he thinks it's cool.

While, amazingly, Brisingr doesn't sound as bad as Eldest, it's going on the very bottom of my reading list.