It is more difficult to imagine the fabrication of hard stone vases with long narrow necks and rounded bellies. Metamorphic schist is harder than iron. The diorite used, a granitic rock, is among the hardest known. Modern sculptors do not attempt to carve these varieties of stone. Yet, these vessels were made before the introduction into Egypt of metals strong enough to cut hard stone.
Numerous vessels have long, narrow necks and wide, rounded bellies.
Their interiors and exteriors correspond perfectly. The tool has not been imagined that could have been inserted into their long necks to shape the perfect, rounded bellies. Smooth and glossy, these vessels bear no trace of tool marks. More details in the Geopolymer Library . The properties of geopolymeric binders and cements have been evaluated by several renown international institutions, their quality proven by numerous tests conducted according to the most severe ASTM and DIN Codes.