The Ancient Egyptians built the great pyramids by pouring concrete into blocks high up on the site as opposed to hauling gigantic stones.
The research by material scientists from national institutions adds fuel to the theory that Egyptian craftsman had sufficient skills and materials at hand to cast two tonne limestone blocks which dress the Cehops and other pyramids.
According to Professor Gilles Hug of the French National Aerospace Research Agency and Professor Barsoum of Drexel University in Philadelphia, the covering of the Great Pyramids at Giza consist of two types of stones - one type from quarries and one which is man made.
The pair used X-rays, electron microscopes and a plasma torch to compare small fragments from pyramids with stones from local quarries at Toura and Maadi.
They found 'traces of a rapid chemical reaction which did not permit natural crystallisation' a reaction inexplicable if the stones were quarried but very comprehensible if the stones were cast like concrete.
It is believed the castings were used only on stones which were on the higher levels of the pyramids.
Source: www.timesonline.co.uk/article/0,,13509-2480751,00.html