This fragment has two worked surfaces. One is slightly curved into a partial "u", with a rounded edge joining it to a second perpendicular surface with a flared edge.
From Nubia (Sudan), Kerma, K III 2(1)a. 1914: Excavated by the Harvard University–Boston Museum of Fine Arts Expedition; assigned to the MFA by the government of Sudan.
Harvard University—Boston Museum of Fine Arts Expedition