The littoral Haut Normand is made of chalk cliffs with silex layers. The rough weather together with the surf of the waves cause the cliffs to erode and slip into the sea.
d to the North by the tides, up to the south part of the bay of the Somme where they are deposited for more than 5000 years in parallel ridges to the shore. Since the second half of the XIX century, these stones of blue silex called "Ceramic Rolling Stones", very pure in silica (more than 99% of SiO2) are exploited for the manufacture of tiles as charge in the powdering mills or, after calcination, directly incorporated to the ceramic paste.
The company today :
produces 15000 T cristobalite, calcination at 1600°C :
65000 T clair granulate, calcination at 900°C :
20000 T non-calcination products :