From the molten basements of the world, two hundred miles down, it comes. One crystal in a seam of others. Pure carbon, each atom linked to four equidistant neighbors, perfectly knit, octahedral, unsurpassed in hardness. Already it is old: unfathomably so. Incalculable eons tumble past. The earth shifts, shrugs, stretches. One year, one day, one hour, a great upflow of magma gathers a seam of crystals and drives it toward the surface, mile after burning mile; it cools inside a huge, smoking xenolith of kimberlite, and there it waits. Century after century. Rain, wind, cubic miles of ice. Bedrock becomes boulders, boulders become stones; the ice retreats, a lake forms, and galaxies of freshwater clams flap their million shells at the sun and close and die and the lake seeps away. Stands of prehistoric trees rise and fall and rise again in succession. Until another year, another day, another hour, when a storm claws one particular stone out of a canyon and sends it into a clattering flow of alluvium, where eventually it finds, one evening, the attention of a prince who knows what he is looking for.
It is cut, polished; for a breath, it passes between the hands of men.
Another hour, another day, another year. Lump of carbon no larger than a chestnut. Mantled with algae, bedecked with barnacles. Crawled over by snails. It stirs among the pebbles.