Umber

Umber is a natural brown earth pigment that contains iron oxide and manganese oxide. [2] In its natural form, it is called raw umber. When calcined, the color becomes warmer and it becomes known as burnt umber.

Its name derives from terra d'ombra, or earth of Umbria, the Italian name of the pigment. Umbria is a mountainous region in central Italy where the pigment was originally extracted.[2] The word also may be related to the Latin word umbra, meaning "shadow".[3]

Umber is not one precise color, but a range of different colors, from medium to dark in value, from greenish to reddish in hue. The color of the natural earth depends primarily upon the proportions of iron oxide and manganese in the clay.[3] Umber earth pigments contain between five and twenty percent manganese oxide, which accounts for their being a darker and less saturated color than the related earth pigment, sienna.[4] Commercial umber pigments vary in color depending on their origin and how they are processed. Not all pigments marketed as "umber" contain natural earths; some contain synthetic iron and manganese oxides. Pigments containing the natural umber earths are typically identified by the Color Index Generic Name, PBr7 (Pigment brown 7).

https://en.wikipedia.org/wiki/Umber