RockTalk: Gold in Colorado

This edition of RockTalk explores the history of gold in Colorado, how it is mined, and what it is used for. Digital PDF download. RT-06-02D

From the Introduction:

What is it about gold that makes it so attractive and so useful? Gold is not very hard; a knife can easily scratch pure gold. Gold is very heavy or dense, having a specific gravity of 19.3 (extremely heavy even for metallic minerals). Some of the other characteristics of gold are ductility, malleability and sectility, meaning it can be stretched into a wire, pounded into other shapes, and cut into slices. Gold is the most ductile and malleable element on our planet. A single ounce of gold can be drawn into a wire 35 miles long and it can be hammered into sheets less than five millionths of an inch thick. Gold is a great metal for jewelry, as it never tarnishes.