Paying zakaat on gold and cash together

For zakaat, the cash is totaled up and 2.5 % is to be paid, but gold jewellery and silver are they separate? For example, someone has gold above the nisaab amount, they evaluate its worth and separately, calculate 2.5 % from its worth, or do they add its worth to the cash total and pay 2.5 % on the lump sum? Or do the cash amount and gold amount separately?