St. Piran's Blade
From PotC Wiki
St. Piran's Blade was a magical sword. Outwardly, it appeared to be a normal sword, though it blazed with fire in the hands of someone with a pure heart. The sword was stored in a case full of gold and jewels.
The sword was centuries old by the time Jack Sparrow ultimately discovered it, and for a long time, no one knew its location. Sparrow managed to locate it, but his crew accidentally sank the vessel carrying it. Through a bit of trickery, Jack was able to retrieve the sword from the bottom of the sea. Elizabeth Swann and William Turner insisted the sword be given to a museum, but Jack was able to keep the treasure-filled sword case.
