Commentary for Genesis 2:12

והבדולח, Rabbi Saadyah gaon, as well as Ibn Ezra say that it is a small spherical white gemstone. This is supported by the reference to כעין הבדולח in Numbers 11,7 where the Torah describes the appearance of the manna. The same scholars believe that this stone is formed by what were originally small drops of dew which had descended on that river. This is the reason why this “stone” is round, just as a drop of dew. Seeing that each individual such stone is so small that it is useless as an effective tool in commerce and industry, this is the reason why the word אבן is not mentioned in connection with בדולח, as opposed to the שהם gemstone which is specifically described as a “stone.” The latter is a large stone, and many different kinds of vessels are made out of its material. Due to its cost, these vessels are found only in the homes of kings and wealthy individuals. The shoham stones on the epaulets of the High Priest had the names of the twelve tribes etched into them. (Exodus 28,9) This gemstone was chosen in preference to others as it is more precious than most, and is found in an almost pure form, not containing any flaws due to discolouration.
This river flows in an easterly direction and does not continue through the ארץ חוילה, but flows around it and then enters the sea on its eastern shores. The reason most people called this river Pishon is because its waters help seeds irrigated by them to expand and produce substantial crops. Etymologically, the word פישון, is a derivative of the word פוש found in Jeremiah 50,11 כי תפושו כעגלה דשה, “when you stamped like a heifer treading grain.” Onkelos renders the word פרו, “be fruitful” as פושו in Genesis 1,28.

וזהב הארץ ההיא טוב, “and the gold originating from that area is good.” What is meant is that it lends itself to amalgamation with copper, without losing its appearance as gold. Actually, this is no more than logical; if the gold found in the rivers emanating from Gan Eden was “good,” the gold inside the garden surely must be good.