When you want to make a kiln for glassmaking, you search continuously for a propitious day during a favorable month. You lay the foundations of a kiln with four chambers. You make constant offerings and set up purifying divinities so that no impurities may enter: you make lapis lazuli.
These instructions summarize the contents of a corpus of Akkadian glassmaking recipes from more than two and half millennia ago. It was then, in the seventh century BCE, that the king himself claimed to have dedicated clay tablets containing instructions “for your making stones” (colored glasses and frits) to the temple of Nabu and Tašmetu, the patron gods of knowledge: