Green Earth (PG 23) is a mineral pigment with a wide variety of shades: from deep olive green to emerald or even blue green. Since Green Earth is a transparent colour it works perfectly for glazing techniques.
Icon painters used Green Earth a lot, especially in frescos. Also this colour was very popular in Italy, where it was named as Verona Earth Green after a production location. The best Verona Earth Green had cool green shade, which is not available anymore because of landslide happened in 1922. This pigment is still being manufactured at this place, but the quality is lower than it’s used to be.
Medieval painters used Green Earth for portrait underpaintings, because it neutralized flesh colours. Vermeer, on the contrary, used Green Earth on top of flesh colours, for example, in Girl with a Red Hat, The Guitar Player, A Lady Standing at a Virginal, A Lady Seated at a Virginal, and The Allegory of Faith. Although Green Earth was actively used even after 15th century, it was gradually replaced with umbers due to their warmer and more natural shades.
Since paint’s characteristics depend on manufactures and places where certain pigment is derived, we can’t say for sure which shade your Green Earth will take. However, basically paints based on Green Earth are transparent, light-fast, and don’t like to be mixed with cadmium yellow.
Rusart has Green Earth in Maimeri Classico product line.