Exodus 32:20

“And he took the calf which they had made, and burnt it in the fire, etc.] Melted it down into a mass of gold, whereby it lost its form, and had no more the appearance of a calf: and ground it to powder; but how this was done is not easy to say, whether by beating the mass of gold into thin plates, and then filing them small; for this art has remained unknown; the chemists have boasted of it as only possessed of it; but it seems Moses, learned in all the learning of the Egyptians, had it: however, it is now certain by various experiments, that gold, though a very thick and heavy body, consists of parts which are separable from one another, and to be divided into infinite subtler parts: the…”

“he took the calf which they had made, and burnt it in the fire, &c.--It has been supposed that the gold was dissolved by natron or some chemical substance. But there is no mention of solubility here, or in Deu 9:21; it was "burned in the fire," to cast it into ingots of suitable size for the operations which follow--"grounded to powder"; the powder of malleable metals can be ground so fine as to resemble dust from the wings of a moth or butterfly; and these dust particles will float in water for hours, and in a running stream for days. These operations of grinding were intended to show contempt for such worthless gods, and the Israelites would be made to remember the humiliating lesson by…”

“The faithfulness of Moses in the office that had been entrusted to him was now to be put to the test. It was to be made manifest whether he loved his own glory better than he loved the brethren who were under his charge; whether he would prefer that he should himself become the founder of a “great nation,” or that the Lord’s promise should be fulfilled in the whole people of Israel. This may have been especially needful for Moses, in consequence of his natural disposition. See Numbers 12:3; and compare Exodus 3:11. With this trial of Moses repeated in a very similar manner Numbers 14:11-23, may be compared the trial of Abraham Genesis 22:0 and of our Saviour Matthew 4:8-10. Exodus 32:8 These…”

“He burnt the calf - Melted it down, and then filed it to dust; and that the powder to which it was reduced might he taken notice of throughout the camp, he strawed it upon the water which they all drank of. That it might appear that an idol is nothing in the world, he reduced this to atoms, that it might be as near nothing as could be. Exodus 32:21”

“32:20 Passing the gold powder of the image through the bodies of the people effectively rendered it unclean.”

“took the calf: How truly contemptible must the object of their idolatry appear, when they were obliged to drink their god, reduced to powder, and strewed on the water! Some have asked, how gold, the most ductile and ponderous of all metals, could have been stamped into dust, and strewed on the water. In Deu 9:21, this is fully explained. I took, says Moses, your sin, the calf which ye had made, and burnt it with fire; that is, melted it down, probably into ingots or gross plates, and stamped it, beat it into thin lamine, something like our gold leaf, and ground it very small, even until it was as small as dust, which might be very easily done by the action of the hands, when beat into thin…”

“He then proceeded to the destruction of the idol. "He burned it in (with) fire," by which process the wooden centre was calcined, and the golden coating either entirely or partially melted; and what was left by the fire he ground till it was fine, or, as it is expressed in Deu 9:21, he beat it to pieces, grinding it well (i.e., crushing it with and between stones), till it was as fine as dust. (Note: There is no necessity to refer to the process of calcining gold, either here or in connection with the destruction of the Asherah by Josiah ( Kg2 23:4, Kg2 23:12; Ch2 34:4, Ch2 34:7), apart altogether from the question, whether this chemical mode of reducing the precious metals was known at all…”