Dealer - person who buys and sells (not necessarily just gold) Goldsmith - person who works gold into other things e.g. jewellery Jeweller - person trading in jewellery (not necessarily just gold)

There is no term analagous to "fishmonger" for a seller of gold. If the gold is in jewelry, we would call the person a "jeweler" (or the British spelling is "jeweller"). If the person buys and sells gold but not jewelry, they would be called a "gold dealer". There might be some areas of the world where a specific term has been created that is like "fishmonger" but that term would be used locally or regionally.

jeweller