gold dust

It is sometimes argued that gold is a crisis proof investment. One is then usually offer gold bullion, but what about gold dust? Gold that has been mined, but wasn't processed further yet. Is it wise to purchase commodity gold or should one rather go for processed gold like gold bullion or gold coins. I am asking, because I am also looking into gold from Zimbabwe. Something that might become a profitable business in the future, when this country stabilizes again.