What Is White Casing Stone?

Stone Material

• White casing stone, so called because it encases and protects the inner stones of the structure, is technically hard, durable white limestone mined near the Great Pyramid. When polished, it resembles white marble, but it is firmer and bears up better against natural elements than marble. Lower grade soft limestone was used to construct the core of the pyramid.

Number and Placement

• There were originally 144,000 white casing stones covering the pyramid. They were all 100 inches (8.3 feet) thick and weighed 20 tons. All the casing stones were cut so precisely they were within 1/100 of an inch of being exactly straight and were placed on all four faces of the pyramid at almost perfect right angles. Each of the massive stones had gaps between them of 2/100s of an inch wide that were filled with white cement that sealed out water and moisture, a sealant so strong most of it remains unbroken and free of cracks, proving it was harder than the white casing stones. The luster of the stones, which covered 5 1/4 acres of the pyramid’s surface, was reportedly brilliant enough to be spotted from the moon.

Interior Construction

• The interior of the Great Pyramid is comprised of soft limestone blocks that range in weight from 4,000 to 40,000 lbs., although it is impossible to know how many were used without destroying the pyramid. The pyramid’s cornerstones have ball-and-socket joints that give the structure the ability to gently sway during earthquakes, settling and the contraction and expansion caused by cold and heat.

Casing Stone Fate

• The white casing stones remained intact until the 13th century when an earthquake struck the Great Pyramid region and some of the stones were dislodged. Local Arabs quickly grabbed the loose, perfectly cut and polished stones and used them in constructing mosques and palaces. Some of the casing stones were used to reconstruct the city of El Kaherah and build the Mosque of Sultan Hasan. Since the 13th century, no white casing stones have been removed from the Great Pyramid.