This is a fragment of an amulet made of lapis lazuli (fits with 29-11-394). The amulet represents the djed-pillar. The pillar, which symbolized the spinal column of the funerary god Osiris, was the hieroglyphic symbol for stability.
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