This is a large rosette disc that is bored lengthwise. One side is decorated with a relief of an eight-petaled rosette.
From Egypt, Giza Mastaba G 2385, room F. 1913: excavated by the Harvard University–Boston Museum of Fine Arts Expedition; assigned to the MFA in the division of finds by the government of Egypt. Findspot Information: Giza G 2385 F
Harvard University—Boston Museum of Fine Arts Expedition