The Singing Bowl is the fifty-fourth treasure that can be found in Uncharted 2: Among Thieves.
The Singing Bowl is found in Chapter 16 - Where Am I?. The third and final treasure is found adjacent to the elder's house. Be certain that you don't walk up to the stairs leading to the elder's front door, or you're going to catalyze a cutscene and will be forced to replay the chapter (not that that's really a big deal or anything). Simply look along the side of the elder's home. The treasure should be sitting next to a tree, securely in the tree's gigantic shadow.