This is a smaller piece from a larger 1 Kg stone found at the Great Pyramid of Egypt at Giza.  It had been broken off from a large block at the base.  Just think- this is from the first foundation layer that workers laid to build the pyramid, 4500 years ago!  It is made of limestone unique to the pyramids, quarried some distance from the structure itself.  Pieces could be identified as to authenticity by the fossils in the stone.
The piece is rare, since the pyramid is now heavily guarded.  We were at the pyramids in 1990 and persuaded the guards to allow us to visit at night.  No damage was done to the pyramids.  We were taken on a special tour after hours to visit the ruins of the pyramid workers which are off-limits to the public.  There are other stone pieces from the area for sale, but this came from the pyramid itself.
The piece is about 5/8"x 1/2"x 1/8" and weighs about 0.04 oz.