what is the name of the stone by which the great wall of china is made

It is made of three different types of stone. The best known is granite (magmatic rock), but there is also white marble (metamorphic rock) as well as green and white stones (sedimentary rock, like sandstone and limestone). The stones came from the surrounding mountains. The first sections built with stones date back from the Contending Kingdoms. At that time, the Chinese simply piled up the stones, one on top of the other. The strength of the walls didn’t improve itself as the years went on, thanks to the evolution of the civil engineering’s techniques, but thanks to the improvement of the weapons. Later on, walls were built with quarry stones (roughly-carved stones). As granite was very strong and hard, an advanced technology was required to hew it. We can see nice chipped stones as of the Ming Dynasty. From the very early brick constructions, stones are often used to build strong foundations, but rarely as vertical clamping (crossing of rocks, from which we can see the sides as a decoration) For the parts of the wall crossing rivers, boats filled up with iron and granite were drowned on purpose, for foundations.