Fig. 1. Granite core (UC16036) from Giza of 4th Dynasty date. (height. 11 cm. The Petrie Museum, Photograph by Jon Bodsworth The Egypt Archive)
"Gizeh UC16036 Granite Core from Tubular Drill Hole. Pyramids & Temples of Gizeh, VII, 7; p. 77. Tools & Weapons, LII, 59; p 44. Dyn. IV"