Genesis 2:11

The name of the first is Phishon; that is it which compasseth all the land of Hindiki, where there is gold.

THE LAND OF HAVILAH, WHERE THERE IS GOLD. This is to explain that it is not the Havilah of Egypt, concerning which it is said, And they dwelt from Havilah unto Shur, that is before Egypt, for this one [referred to here] is in the extreme east. The verse mentions also, There is the bdellium, in praise of the river, that in the sand that is in it and on its bank there is found that good gold, the bdellium and the onyx stone. For these things are found in rivers; in some, silver can be found. Similarly, the bdellium and precious stones are found mostly in rivers.
In the opinion of former scholars, Pishon is the Nile of Egypt; it compasses this entire land of Havilah, and comes from there and passes the whole land of Egypt until it falls into the great sea at Alexandria in Egypt.

שם אחד פישון, [The Torah] informed us of the praise of the river that irrigates the garden that is not known to us by informing us of the rivers that branch off from it that are known by their praised size and the goodness of their water and the goodness of their fruit.

שם האחד, it appears from the Torah’s report that the land called חוילה was situated in the immediate vicinity of Gan Eden, and that this is the reason that it is a land superior to other parts of the earth. Just as Gan Eden is superior to other parts of the globe due to its superior trees and their fruit, so this land חוילה has other advantages, as the Torah enumerates, i.e. that this is where gold is found. The reason the Torah prefaced the word זהב with the letter ה, as if speaking of a special kind of gold, is that although gold can be found in other countries also, it is more abundant in this land known as ארץ החוילה. The Torah itself states that the gold found there “is good,” suggesting that instead of quartz containing gold being found there, gold nuggets who are pure gold were there in abundance. Perhaps, being so close to Gan Eden was the reason why gold was found there in abundance and the Torah suggests that the Gan Eden which has been lost to mankind, did indeed exist, to wit that even a land only bordering on it, shows that it is superior to other countries on our globe. The shoham “jewels,” [type of gemstone, which according to Rabbeinu Bachya possessed therapeutic qualities for its wearer and was used later in the garment (ephod) of the High Priest, could also be found there. [Exodus page 1293 this editor’s translation of Rabbeinu Bachya’s commentary]