This is a fragment of an elbow and part of the back of a statuette. The stone is dark gray granite with many small pink feldspar inclusions and mica inclusions.
From Nubia (Sudan), Kerma, K III 4(1). 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 Sudan. (Note check provenance and number as 14-2-1135 are all K X 1078).
Harvard University—Boston Museum of Fine Arts Expedition