reverse charge for gold

You need not apply reverse charge in it as reverse charge is currently suspended.

The sale of old jewellery by an individual to a jeweller will not attract the provisions of Section 9 (4) of the GST act and the jeweller will not be liable to pay tax under reverse charge mechanism on such purchases, .However, if an unregistered supplier of gold ornaments sells it to registered supplier, the tax will apply under reverse charge mechanism But that to also deferred to 30/09/2019, by vide Notification 22/2018

Hence its treated as exempt supply

need to disclose GST return Old Gold purchase from unregistered person.