Colouring materials and gem resemblances

Meaning

The colouring series assigns saffron to yellow amber, pine soot to black, verdigris to green resembling a blue stone or turquoise, and green juice to emerald-like material. Lazurium gives the sapphire comparison; brazilwood, garnet or ruby; purple colour, amethyst; ceruse, alabaster. These are named colour-producing materials within an argument about tincture and coagulation, not proof of gemstone identity. Some names are specific ingredients, others broad descriptions; “green juice,” especially, does not identify a botanical species.