Burnt umber is the calcined, or heated, version of raw umber, which is a natural brown to reddish-brown earth pigment. This pigment contains both iron oxide and manganese oxide, and is generally a bit darker than other similar pigments, such as ochre and sienna. Heating raw umber dehydrates the iron in the pigment, which results in a more reddish hue. That said, however, please keep in mind that this is indeed an altered version of a naturally-occuring pigment, so there may be a slight degree of variation between batches. This deserves mention because umber -- both raw and burnt -- doesn't refer to just one specific color. Rather, the term refers to an entire range of colors. The term 'umber' is derived from the Italian 'terra di ombra', or earth of Umbria (an Italian region where umber was initially mined). In the ceramic world, burnt umber is most typically used as a body stain in light- or white-colored clays. Calcined iron source containing significant silica, manganese, and calcia. Often used for staining clay bodies.
