Fig. 19

Microscopic photograph shows the structural mortars joining the backing limestone blocks of Chephren pyramid. Very fine to coarse-grained, showing prophyrtic texture (fine to medium-grained of quartz, gypsum and rock fragments enclosed in very fine-grained matrix). Significant amounts of irregular pore space are detected in the sample. The sample is composed of gypsum, anhydrite and rock fragments (composed mainly of calcite) associated with minor amounts of quartz, biotite, iron oxides and opaques cemented by very fine-grained matrix of gypsum admixed with calcite, anhydrite, halite and iron oxides