'Hill tribe silver' would not pass muster as 'silver' in any recognised western jewellers. It is an impure alloy with, in most cases, a silver content of barely over 50% and items made with it are invariably so weak and fragile that they easily and quickly break.

The silver shops already mentioned in Royal Garden by Francois are a far better bet (although, of course, you will have to pay for the 'real thing').