The Silver Official Seal is the seventy-sixth treasure that can be found in Uncharted 2: Among Thieves.
The Silver Official Seal is found in Chapter 22 - The Monastery. The next treasure we'll bring you to is actually near the stationary machinegun. Head forward from the gun and towards the broken stone wall to your right. Drop down towards the gap in the wall along the water, and hang from the edge of the dock there. On the far side of the broken wall are some red pieces of wood you can grab onto. Pull yourself upward towards the glowing orb hanging off of one of the red pieces of wood, and claim your treasure while hanging there.