Kort och informativ film och guldets ursprung.
http://ed.ted.com/lessons/where-does-gold-come-from-david-lunney?utm_campaign=&utm_medium=referral&utm_source=facebook.com&utm_content=lesson&utm_term=science (http://ed.ted.com/lessons/where-does-gold-come-from-david-lunney?utm_campaign=&utm_medium=referral&utm_source=facebook.com&utm_content=lesson&utm_term=science)