I wondered whether a diamond grown in a lab could carry the same emotional weight as the real thing, without the guilt. And really, if it was identical to a natural diamond down to every last atom, as Roscheisen swore it was, what does it even mean to be the real thing? ... A carbon atom has four electrons in the shell around its nucleus—four little guys just looking to bond with electrons of other atoms. If four of those electrons form single bonds with, say, four hydrogen atoms, you’ll get CH4, methane. If the carbon atoms bond with more carbon atoms in a layered, chicken-wire pattern, you’ll have graphite—just one of many forms of pure carbon. ... So when you think about it, diamonds are a life force in its mightiest form: The densest, hardest, strongest expression of carbon, the element underlying all of life on earth. ... As scientific knowledge goes, our understanding of the conditions that cause carbon to bond this way, or exactly how long it takes, is limited. That’s because it occurs over 100 miles inside the planet, at extreme temperatures and pressures. Many of the world’s diamonds were formed billions of years ago, and scientists don’t know exactly how those carbon atoms got down there inside the mantle to begin with.