Albert Barnes Commentary Job 28:17

"Gold and glass cannot equal it, Neither shall it be exchanged for jewels of fine gold." — Job 28:17 (ASV)

The gold and the crystal - A crystal, in chemistry, is an inorganic body which, by the operation of affinity, has assumed the form of a regular solid, terminated by a number of plane and smooth surfaces. It is found in various forms and sizes and is composed of a great variety of substances.

The common “rock crystal” is a general name for all the transparent crystals of quartz, particularly of clear or colorless quartz. “Webster.” The word used here (זכוּכית zekûkı̂yth) occurs nowhere else in the Bible.

It is from זכה zâkâh—to be clean, pure; and is given to the crystal on account of its transparency. In Arabic, the word means either glass or crystal.

Jerome translates it, “vitrum”—glass; the Septuagint, ὕαλος hualos—crystal, or the “lapis crystallinus.” Hesychius says that the crystal denotes λαμπρὸν κρύος lampron kruos—“clear ice,” or, λίθον τίμιον lithon timion—“a precious stone.”

There is no reason to suppose that “glass” was known as early as this, and the probability is that the word here denotes something like the rock crystal, having a strong resemblance to the diamond, and perhaps then regarded as nearly of equal value. It cannot be supposed that the relative value of gems was understood then as it is now.

Jewels of fine gold - Margin, “vessels.” The Hebrew word כלי kelı̂y properly means vessels, or instruments. It may refer here, however, to ornaments for the person, as gold was chiefly employed in that way.