This is a circular lid (or, less likely, a token) shaped from a fragment of a red-brownware pottery vessel. It has a slight concavity due to the portion of the original vessel from which the source fragment broke off. It may have been used for an offering/model vessel.
From Kerma, Cemetery S, grave 1626. 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: September 19, 2006)
Harvard University–Boston Museum of Fine Arts Expedition