Khafre's Diorite Statue

In this video series, we will be taking a look at some remarkably sophisticated stoneworking that is on public display in the Cairo Museum, beginning with the famous black diorite statue of Khafre, ruler of Egypt circa 2550 BCE, discovered in 1860 by Auguste Mariette upside down at the bottom of a pit filled with rubble in the antechamber of the Valley Temple. This sculpture was immediately seized upon by academics as proof of the ruler's creation of the second largest pyramid on the Giza Plateau as well as the Sphinx, the Sphinx Temple, and the Valley Temple, in spite of the conflicting account recorded on the inventory stelae that assigns the role of restorer rather than originator to the fourth dynasty pharaoh. This statue of Khafre was carved from a single block of black diorite, a coarse-grained igneous rock formed by a mixing of basaltic and granitic magmas deep underground, then subjected to a period of prolonged cooling, resulting in a material with a Mohs hardness of 6.5. For comparison, modern steel has a hardness of 5.5, bronze is 4, and copper is 3. Let me emphasize that this material absolutely cannot be worked with the copper and bronze tools displayed in the Cairo Museum, and even steel tools need to be hardened and specially tempered to sculpt it. This statue, along with a few other similar works in the museum, captures my attention completely, along with many other visitors who encounter it. The skillful figurative representation, bilateral symmetry, and glass-smooth polished surfaces, all executed flawlessly in one of nature's hardest materials, with a seeming ease and flair, makes for a breathtakingly beautiful artifact. My examination of the statue was conducted on two occasions in late 2019, and was confined to a close visual inspection, digital photography, and digital microscopy of four areas, at a magnification of 500 times. These micro-photographs are presented at the end of this video. Starting with a walk around the statue to photograph points of interest, the first feature that arrested my attention was the rear surface. Planed absolutely flat and polished to the same luster as the rest of the statue, the tail feathers of the garden horus as falcon project from it at top. It is apparent that approximately 20 or so millimeters of material was removed across the breadth and height of the block of stone, just so that those feathers carved from the same block could gracefully overhang it. A tremendous amount of work to perform for the sake of such a small detail. Visible along the sides of the thighs and torso, as well as the calves and feet, are smooth and regular undercuts proportional to the adjacent features, with even radii of cut. The toes even display nails and cuticles, with delicately incised edges. On the base of the statue are hieroglyphs carved next to the feet, and running from front to rear midway up the sides are a pair of horizontal grooves. These features are curious in that they are uneven, very in-depth, and have chipped edges, quite at odds with the level of execution seen on the rest of this artifact. Current methods of achieving a smooth polished surface on granite and diorite utilize progressively finer diamond dust impregnated abrasive pads, starting at 200 grit and working up to over 3,000 grit, applied by mechanical disc sanders or vibrators, powered by compressed air or electricity. Academic sources cite the use of quartzite rubbing stones to achieve the initial surface smoothing after sculpting, followed by using a quartz dust impregnated piece of cloth or leather pad and lubricant as the method employed by the ancient Egyptians. Rotating polishing discs leave overlapping circular scratch patterns, with consistent radii ranging in size from the outer diameter of the pad to the minimum, created by a bracing on or close to the center of the disc, which tend to resemble fine spirals. Some types of mechanical vibrating sanders, such as the sort commonly employed by professional bobby shops, leave straight or cross-hatched scratch patterns anywhere from 30 to 50 degree angles from each other, typically with short stroke lengths of only a few millimeters. Lastly, hand rubbing with sand and water or quartz grain impregnated cloth or leather leaves a scratch pattern that is random, semi-circular, and varying in stroke length, radii, and direction, and tends to follow irregularities in the surface contour rather than equalize them. We acquired microscopy image captures from the statue's rear vertical surface, the left thigh top surface, the right calf front surface, and the pedestal top near the right foot, and examples are presented here. Note that there is a consistent scratch pattern signature in all four locations of a cross-hatched type with absolutely straight lines in a regular spacing. None of the images show either the swirl marks from spinning pads nor the random lines left by hand polishing. This evidence supports our contention that even as late as the Old Kingdom, stone cutting and polishing methods were in use that clearly did not involve copper tools or hand rubbing with sand. We hope that this video was enlightening. Next in the museum series, we will be examining the hieroglyph carvings in a basalt sarcophagus from the Middle Kingdom period.