[5] First used by the ancient Romans, green earth has been identified on wall paintings at Pompeii and Dura-Europos.

[6][7] The Renaissance painter and writer Cennino Cennini claimed that “the ancients never gilded except with this green” being used as a bole, or undercoating.

[8] SEM/EDAXS data have demonstrated that it is possible to discriminate between these two sources of celadonite in Roman wall paintings through the presence of trace elements.

[9] Spectroscopically, therefore, the analytical challenge is to differentiate between the green earths celadonite and glauconite, and perhaps chlorite, and the copper-containing malachite and verdigris, with the added ability to recognize the presence of haematite, Egyptian blue, calcite, dolomite, and carbon which have been added to change the colour tones.

High quality deposits can be found in England, France, Cyprus, Germany and at Monte Baldo near Verona in Italy.