In Fate/Zero, Rin is given a Mana Compass by her father which she uses in her search for Kotone. I've only seen up to episode 10 but I know she'll appear in a later episode where she will receive the Jewel Pendant which becomes the catalyst to summon Archer in the 5th war and saves Shirou's life.
However I don't remember her Mana Compass being mentioned in Fate/Stay Night, nor can i foresee a situation in Fate/Zero where it would be destroyed. Given how it works it seems to be quite a useful tool Rin could've employed in the 5th war.
So I am wondering, is it stated what happens to the compass, since it seems Rin treasures the Jewel Pendant she was given, since it came from her father, and I would assume she would treasure the compass as well.