the Giza Building Project

Here is something I found a while ago:
Science in Egyptology - X-Ray Analysis and X-Ray Defraction of Casing Stones from the Pyramids of Egypt and the Limestone of Associated Quarries - by Joseph Davidovits - Institute for Applied Archaeological Sciences, Barry University, Florida

Samples from 6 different sites at the traditionally associated quarries of Turah and Mokattam have been studied using thin-section, Chemical X-Ray analysis and X-Ray defraction. The results were compared with pyramid casing stones of Cheops, Teti, & Seneferu. The quarry samples are pure limestone consisting of 96-99% calcite, 0.5% - 2.5% quartz, and very small amounts of dolomite, gypsum and iron-alumino-silicate.

The Cheops & Teti casing stones are limestone consisting of 85% - 90% calcite, and a high amount of special minerals such as opalCT, hydroxy-apatite a silico-aluminate which are not found at the quarries. The pyramid casing stones are light in density and contain numerous trapped air bubbles, unlike the quarry samples, which are uniformly dense.

One casing stone sample from Cheops was tested, which has a red coating on it. Analysis of the red coating distinguished a tremendously complicated geoploymeric system of crystalline hydroxy apatite and brush-ite. This red coating constitutes the key to the geopolymeric system used. The hydroxy-apatite (a calcium phosphate) in the red coating is a mineral found in bone, and brush-ite (another calcium phosphate) is only associated with organic material. The X-ray pattern of the coating indicates a zeolite (synthetic) and opalCT, as found in the other casing stone samples. This coating is undoubtedly made from a pure man-made geopolymeric binding agent. The synthetic zeolite and the other ingredients found in the red coating are the first proof that such a binder was produced in Egypt 4,700 years ago.

This level of technology is far in advance of the traditional plaster and simple lime cement production which is always associated with the technology of Ancient Egypt.