I recently learned about the highly polished white limestone 'cladding' or 'casing' stones Wikipedia says: https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza

I recently learned about the highly polished white limestone 'cladding' or 'casing' stones Wikipedia says: https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza#Casing_stones https://en.wikipedia.org/wiki/Great_Pyramid_of_Giza#Casing_s... > Casing stones > At completion, the Great Pyramid was surfaced with white "casing stones"—slant-faced, but flat-topped, blocks of highly polished white limestone.... Visibly, all that remains is the underlying stepped core structure seen today.[citation needed] In 1303 AD, a massive earthquake loosened many of the outer casing stones, which in 1356 were carted away by Bahri Sultan An-Nasir Nasir-ad-Din al-Hasan to build mosques and fortresses in nearby Cairo.[citation needed] Many more casing stones were removed from the great pyramids by Muhammad Ali Pasha in the early 19th century to build the upper portion of his Alabaster Mosque in Cairo, not far from Giza.[citation needed] ...