The Tibetan Silver Vase is the fiftieth treasure that can be found in Uncharted 2: Among Thieves.
The Tibetan Silver Vase is found in Chapter 15 - Train Wrecked. Another treasure can also be found in the snowy area with all of the train wreckage, and just like the aforementioned treasure, you'll probably want to wait until the firefight around you ceases before you go searching for it. If you're facing the fiery wreckage that exploded at the end of the fighting, the treasure can be found on the left side of this area suspended up near the roof on the left side of the train cart that is off the ground suspended by one of the other carts. (Or go Left from where you get the M32 Hammer on top of the cart, look at the outside).