The red surface was created by application of ochre prior to firing in an oxidizing atmosphere and polishing with smooth stones/pebbles.
From Kerma, Cemetery S, grave X-B. 1914: excavated by the Harvard University–Boston Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of the Sudan. (Accession date: July 14, 2006)
Harvard University–Boston Museum of Fine Arts Expedition