Dear Shoaib,
Let me accept that most of jewellary business is running in cash mode only (even not properly accounted), but now because of digitalization and Government's intention to unearth black currency, things are becoming difficult.
So, officially [as per section 40A(3) of IT act] you cannot purchase or expend anything in cash for more than Rs.10000/- on any single day/event, unless on bank holidays etc. etc. (but customer's identity to be procured).
Though it is a big tussle between department and businessmen, but you don't have any other option. Sorry!!