Re: What is Diarite? I can't kind find it listed in any Geological Refs

You can't find it listed anywhere because it's spelled diorite.

Diorite is a fairly-common coarse-grained igneous rock, as is granite, but composed of slightly different proportions of minerals. Igneous rocks form when magma (molten rock) cools and solidifies and diorite is coarse-grained because it cooled slowly deep within the Earth. Diorite often has a "salt and pepper" appearance because it's composed of black and white colored minerals (see picture) although it may also be uniformly gray or black in color. Diorite is typically composed of the minerals sodium plagioclase feldspar, hornblende, and biotite mica and possibly small amounts of potassium feldspar and quartz (visit the Mineral Gallery for information about each of these minerals).

Diorite is a hard and durable rock but I wouldn't call it the hardest rock on Earth since it's composed of essentially the same minerals that many other igneous rocks are. It's hardness is comparable to that of granite.

The Egyptians mined diorite from different quarries throughout Egypt for use as a building stone and also for carving into scuptures (here's a photograph of a diorite sculpture of the Pharaoh Khafre). The Egyptian Ministry of Tourism maintains a web page providing extensive information about the History of Egypt including mentions of diorite being used as far back as the Upper Paleolithic Period (30,000 - 10,000 BC).

For more information about Egypt, there is a web site called Giza On Line which contains links to numerous web sites including one discussing stone-cutting technology. Be aware, however, that this site lists both legitimate scientific information along with information I would consider to be pseudoscience (information which pretends to be scientific but isn't well supported by data). Unfortunately, Egyptology is a field of study riddled with people (usually amateurs without any scientific training) who make claims about the ancient Egyptians which can not be supported scientifically. Many archaeologists may strongly disagree with some of the information presented at this site.

I think most archaeologists would agree that there's nothing especially mysterious about stone work done by the Egyptians since many ancient peoples around the world were able to do amazing things with stone using very simple tools and a lot of patience.