A brown earth that is darker than ocher and sienna, consisting of iron oxide and
oxyhydroxide with manganese oxides, clay, and lime. Highly valued as a
permanent pigment, it may be used in its greenish brown natural state (raw
umber) or in the dark or reddish brown calcined state (burnt umber). CF:
ocher; sienna.
Source:
Dictionary of Mining, Mineral, and Related Terms
