An archaic common name for umber, a dark brown earth pigment contains silica, clay, and a mixture iron hydroxide and manganese dioxide. The name brown chalk was used prior to the 1800s when chemical compound names were standardized (Schur 1985).
S. Schur, "Conservation Terminology: A Review of Past & Current Nomenclature of Materials", Technology and Conservation, 1985.
Sources Checked for Data in Record
- Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985