Before the crucible could be placed into the magma stream, a final assay of the starlight silt was needed to verify its sight and magnetic purity. In Entry hall 715, flanking the eastern wall of the deep gap, the ancient builders had built a series of four tiered settling pools of polished black granite, fed by a diversion water chute of earth-heat stone steam.
Over ten thousand years, the fiery steam had condensed against the cold granite walls, depositing its tiny suspended specks into these quiet pools. The heaviest fiery ash had settled in the first pool. The quartz crystals had dropped in the second. The iron oxides in the third. And here, in the fourth pool, only the finest, purest specks of extraterrestrial starlight silt had piled up.
Qiao Ming knelt beside the fourth pool, his bare horn-hard feet resting upon the granite coping stone. The water in the basin was clear as air, six inches deep, covering a bed of pale, glowing cyan settled mud two spans thick. The silt did not look like sand or mud. It looked like a bed of powdered turquoise that emitted a nonstop, cold soft glow visible even in full daylight.
Behind him, Yan Zhiqiu held the horn lantern back, allowing the natural eerie glow of the pool to light up the chamber. The light cast delicate, dancing ripplets of cyan radiance across the black granite ceiling, creating the illusion of a sunken galaxy resting beneath forty leagues of ocean bedrock.
