Are we to estimate zakat as 2.5% for manufactured gold in addition to manufacturing fees or just according to the standard value of gold?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

If gold reached the Nisaab and then one lunar year passed, it is obligatory to pay a fourth of a tenth (i.e. 2.5%) of its weight, as long as its market price is equivalent to its (value by) weight. However, if the market price exceeds its weight, then it is the market price that counts and not the weight. Therefore, the due zakat on manufactured gold is a fourth of a tenth of its market price and not of the standard value of gold.

Allaah knows best.