Three mineralogical articles are particularly relevant to a study of the pigment, green earth. First of all, an article on the x-ray diffraction classification of glauconites is useful as a basis for the identification and classification of green earths, as well as an explanation of their hetero geneity. A second article on the infrared spectroscopy of layer silicates, including celadonite, is important as the basis for another method of identification of green earths and possibly, the differentiation of celadonite and mineral glauconite. A third article, written in 1820 on the terre verte mines near Verona, Italy, is invaluable for its wealth of information about a traditional pigment source.