The Jeweled Statue Crown is the forty-second treasure that can be found in Uncharted 2: Among Thieves.
The Jeweled Statue Crown is found in Chapter 12 - A Train to Catch. This is an extremely easy treasure to find, and that's saying something, since you haven't exactly had to strain yourself in finding the other three treasures on this chapter so far. To find it, simply take the zipline down. Once you land, walk leftward and you'll see the on-screen prompt indicating a treasure is nearby before very long. Yes, it's really that easy to obtain, and yes, it's virtually impossible to miss it.