green earth

A natural inorganic green-coloured pigment. In terms of its chemical composition, it is iron and potassium silicate with the addition of magnesium, K•Mg(Fe,Al)SiO2•3H2O. The green colour hue, which can be neutral, yellowish, greyish, or brownish, varies depending on the presence of certain chemical elements in the earth. Burning this pigment produces a brown colour.