***** NOT A TEACHER *****
I am 99.99% sure that you cannot make "gold" a countable noun. I have never heard of "golds." (Of course, I have never heard of a lot of things!)
I should suggest that you need something like:
These gold bars/earrings/etc. have been brought from South Africa.
Furthermore, it might be better to use the active: I brought these gold ____ from South Africa.
Student or Learner