In one of his epistles, Sahl ibn Harun spoke in praise of glass to the detriment of gold:
Glass is a transparent substance that shares in light. It is better to drink from than any mineral or metal. It is not heavy in the hand, and does not conceal the drinker's face from his companions. Its price is nothing to haggle over.
Gold is a transient possession whose mere mention is a bad omen. One of its blameworthy properties is the speed with which it accrues to blameworthy people. It misleads all who keep it, and guards for them its venom. It is furthermore one of the Devil's snares, which is why they say: "Two red things are the ruin of men."*
Glass does not absorb grease, and grime does not stick to it. The only thing needed to wash it clean as new is water. Glass is of all things the most similar to water. As marvelous as are its properties, its manufacture is a marvel greater still.
From The Roving of the Eyes: A Commentary on the Comic Epistle of Ibn Zaydun by Ibn Nubata
*Gold and saffron. (Bywords for lucre and luxury, as in the saying of
Abu Bakr al-Siddiq.)
