Is there bad gold? There is good gold.

Genesis 2:11-12 KJV The name of the first is Pison: that is it which compasseth the whole land of Havilah, where there is gold; And the gold of that land is good: there is bdellium and the onyx stone.

If it is specified that the gold of that land is good, I wonder if there is gold from other areas that is not good.

Perhaps the gold of that land is pure, while gold in other areas is mixed with impurities.