This amulet of polished hematite represents the base of a headrest (fits headrest amulet 29-11-300). Such amulets were common in Late Period burials, where their magic was intended to lift the head of the deceased at the moment of resurrection.
From Egypt, Giza, pit G 7757 A, (tomb of Kheperre) debris of room IV. 1929 : excavated by the Harvard University–Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of Egypt.
Harvard University—Boston Museum of Fine Arts Expedition
Egyptian, Late Period, Dynasty 26, reign of Amasis, 570–526 B.C.