Praise be to Allaah.
If
the jeweller is going to make your gold into jewellery, as you have asked
him to, and then take a fee for his work, there is nothing wrong with
that. But if he is going to make the jewellery from gold that is not
yours, and he will take your gold as payment in addition to his fee, this
is not permissible, because when gold is sold in exchange for gold, the
amounts must be equal, and the transaction must be completed in one
sitting.
And
Allaah is the Source of strength. May Allaah bless our Prophet Muhammad
and his family and companions, and grant them peace.
Standing Committee for Academic Research and Issuing Fatwas.
Fataawaa al-Lajnah al-Daa’imah, 13/503