This had only registered 3/8 by the time i got to the final one in the volcano, despite me finding and applying the 7 so far, so i saved just before the final map stone in Mount Horu with fragment in hand, then went in to apply the fragment (with chievo snapped to check progress) died, and repeated from last save point and it progressed each time i did this until the achievement popped. It also netted me
on the way. Hope this helps.