Lump of mud with string mark (jar seal?), part of an official seal of Menkaura but the name (in cartouche) is obscured by overlapping of impressions.
From Egypt, Giza, Menkaura Pyramid Temple room 22. 1907: excavated by the Harvard University–Museum of Fine Arts Expedition; assigned to the MFA by the government of Egypt.
Harvard University—Boston Museum of Fine Arts Expedition