Under a Metal SkyBy: Philip Marsden Discover the wonders and perils of the earths precious metalswhat they have offered us as humans, and how theyve forever changed our relationship with the world around us The ground beneath our feet is full of riches: the ocher that allowed prehistoric humans to paint on cave walls; the tin that drove the early Industrial Revolution; radium, the source of Marie Curies wonder; and lithium, the essential mineral of modern life found