From People of the Book by Geraldine Brooks:
"Blue: intense as a midsummer sky, obtained from grinding precious lapis lazuli carried by camel caravan all the way from the mountains of Afghanistan."
"White: pure, creamy, opaque. Less glamorous, more complicated than the blue. At that time it would still have been made according to the method discovered by ancient Egyptians. You covers lead bars with the dregs of old wine and seal them up in a shed full of animal dung. The acid in the vinegary wine converts lead to its acetate, which in turn combines with the carbon dioxide released by the dung to make basic white lead carbonate, PbCO3."
"There was yellow, made of saffron. That beautiful autumn flower, Crocus sativus Linnaeus, each with just three tiny precious stigmas, had been a prized luxury then and remained one, still. Even if we now know that the rich color comes from a carotene, with a molecular structure of 44 carbon, 64 hydrogen, and 24 oxygen, we still haven't synthesized a substitute as complex and as beautiful. There was malachite green, and red; the intense red known as worm scarlet-tola'at shani in Hebrew- extracted from tree-dwelling insects, crushed up and boiled in lye. Later; when alchemists learned how to make a similar red from sulfur and mercury, they still named the color "little worm"-vermiculum. Some things don't change: we call it vermilion today."