This fragemnt is the forearm or leg of figure. The stone is black serpentinite with blue-green mottled coloration on the surface.
From Nubia (Sudan), Kerma, K X corridor 5-6. 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.
Harvard University—Boston Museum of Fine Arts Expedition