Industrial processing vats lined with granite panels are able to contain sulfuric acid, hydrochloric acid, nitric acid, bromine, and other volatile and caustic substances. In most granite, the primary minerals are quartz and feldspar, which represent about 90% of the composition of the granite. Quartz and feldspar are non-conductive substances, but they can conduct electricity if enough direct mechanical stress is applied, such as compression. This is known as piezoelectricity. Thermal stress can also induce this effect. Remembering the translation for pyramids as "fire in the middle," I believe the so called sarcophagus is really a vessel used to withstand volatile chemical reactions. That is the reason for the dark burn stains etched into the granite.
Photo of rectangular granite box. Note the dark stains etched into the interior walls and bottom.
Photo of elaborate tunnel system, large enough to drive a semi-truck through. You can no longer go into this area, in the Serapeum at Saqarra, Egypt. It is closed to the public. It contained 24 granite boxes, each weighing 60-80 tons, one weighed 100 tons.
Solid granite boxes with lids cut out of one piece of solid granite were on either side of the tunnel system. Nothing was ever found inside these boxes. Note the heavy encrustation of minerals in the red circle on the ceiling of this underground chamber.
Photo showing the size of these granite boxes.
Photo of box with lid partially removed. Because they are solid granite and so large these boxes could have contained highly volatile chemical reactions.
Photo showing the detail of the workmanship in the one-piece granite boxes. Remember that granite is resistant to acids and other caustic chemicals.
Photo of a granite vessel with a round hole in the bottom. (See red circle.)
Photo of a vessel with a round hole in the bottom. If you were to bury a mummy in a granite box, why would you put a drain hole into it? Wasn't one of the points of mummification to seal off the body so nothing from the outside could destroy it?
Photo of small granite household-type containers or vessels.
Photo of round granite vessel, many of these vessels were intricately carved.
Sealed solid granite vessel, when it was opened it was empty, it was found in Sekhemkhet's pyramid. Note large room with heavy mineral deposits similar to photo #200 in the Serapeum at Saqqara.
It is very unusual for a sarcophagus to have a sliding granite door as per the drawing.
Photo of remnants of upper temple near the base of the pyramid at Abousir. The floor was made entirely of solid blocks of black granite two feet thick. Remember this granite came from over 500 miles away; there had to be something important about it.
Photo of solid black granite causeway.
Photo of solid black two-foot-thick black granite floor at base of Cheops pyramid. (See red arrow.) This is the remnant of a walled upper temple. The walls are gone but the base is still there.
Photo showing Cheops pyramid in background with black granite floor near base of pyramid. Don't forget that granite is a good thermal and electrical insulator, and is resistant to the effects of acids and other caustic chemicals.