Meaning green earth, it is a natural earth pigment used for paint and dyes. It’s a type of ochre that can be found in greensand and similar rocks, occurring in small measure in Provence close to the yellow and red ochres. The celadonite typical of medieval and renaissance painting, which has greenish-grey colour was and is mined in Verona, Italy.
It now refers to the colour itself, and is generally synthetically manufactured.