Theophrastus - History of Stones - Hill…
“ The Ochres all contain more or less Iron; for the yellow ones become red by burning. ↑ Sandarach and Orpiment are also two Substances of the same Nature and Texture, differing in Colour, like the Ochre and Reddle; and, in like manner, the yellow will become red by burning. Orpiment is the Ἀῤῥενικὸν of the antient, and Ἀρσενικὸν of the later Greeks. The Arabians call it Zarnich Asfar: It is a very beautiful Substance, composed of large Flakes, resembling those of the Lapis Specularis, but of a glorious Yellow; very weighty, and sometimes holding a small Quantity of Gold. ”
