In a world where gold can be fabricated with magic, I imagine it would work like IRL diamonds. Synthetic diamonds are relatively cheap to make and just as (or even more) beautiful, but the only ones that have 'value' are the ones extracted destructively and with awful human conditions.
So you could make the caveat that because his gold is not 'genuine', it doesn't have market value.
In a world where gold can be fabricated with magic, I imagine it would work like IRL diamonds. Synthetic diamonds are relatively cheap to make and just as (or even more) beautiful, but the only ones that have 'value' are the ones extracted destructively and with awful human conditions.
So you could make the caveat that because his gold is not 'genuine', it doesn't have market value.