Then Ryan saw it, a smooth black surface, unmarred and perfect. The submarines cleaned the river dirt and blasted rock from the obsidian glass as he watched. The rock seemed to absorb the light from the flood lamps, leaving nothing to reflect. And, as the crews continued, Ryan saw the rock take shape. Its edge was perfectly flat, cut like a gemstone, and obviously created by man or some other sentience, before being buried here long ago. This was no naturally occurring rock. And it was huge, at least ten meters on a side, and seemed to be diamond-shaped, though Ryan had no idea what it would look like once they'd finished the excavation.