BROKEN BLADE (Bureiku Bureido), by Yunosuke Yoshinaga. First published in 2007 and first published in North America in 2009.
PLOT:
Rygart Arrow is a one-in-a-million sort of guy. He lives in a world where people can manipulate quartz to obtain magic energy and fight an endless war, but Rygart is completely unable to do so. His father even went so far as to send Rygart to military school to try and develop some sort of ability, but all Rygart got out of it was a lot of debt and some friends in high places.
Years later, Rygart is summoned by one of those old school friends, who now happens to be king. It seems that the military discovered an ancient mech suit in a quartz mine, but no one has been able to start it. When Rygart climbs in, the suit comes to life, but now Rygart finds himself in a battle against a massive army as well as another old friend.
