Spectrum in a Flask

Ocher is perhaps the most widespread pigment in an artist’s palette and has been known since prehistoric times. Despite its familiarity, defining ocher precisely can be challenging. Is it a type of earth, a mineral, an iron ore, a pigment, or simply a color? And when referring to its color, do we mean yellow, red, brown, or orange? Clearly, the term "ocher" holds multiple meanings. Let's explore them step by step.  A yellow ocher paint swatch A red ocher paint swatch Geological Perspective While commonly associated with iron minerals, ocher has a broader geological definition. It refers to the colorful crusts formed on metalliferous ores as they decompose. Typically, ochers appear as fine-grained oxidation layers or crusts but can also occur as soils or even form entire rocks. Chemically, ochers are mixtures of metal oxides (products of oxidation) and hydroxides (products of interaction with water) with diverse compositions and appearances. Beyond iron ochers, other not...