Amberlight

Tellurith, the head of a great ruling House in Amberlight, inexplicably
finds a battered outlander left for dead in the streets of the legendary city
— and an oracle reveals that he must not die. The man, although stripped
of his memory, may know of a threat to Amberlight's unique possession: the
motherlodes of the qherrique, the pearl-rock that gives their world its most
powerful tool. Tangled in intrigue, insurrection and brutal warfare, it will
take a cataclysmic upheaval for Tellurith and the stranger to begin to grasp the
more-than-human mystery that brought them together.