The Jeweled Silver Brooch is the fifty-fifth treasure that can be found in Uncharted: Drake's Fortune.
The Jeweled Silver Brooch is found in Chapter 16 - The Treasure Vault. This tricky treasure can be found when you reach the second swinging lantern (the one swinging in front of the IV sign). When you reach the top of the stairs before the lantern, stop and turn left to face the III sign on the pillar. Aim yourself diagonally so that you jumps just to the left of the pillar. The jump should be successful and you can claim your prize at the end of the drawbridge.