What is a radiolarite in geology ?

Radiolarite : definition

A radiolarite is a siliceous sedimentary rock formed by the accumulation of skeletons of radiolarians (pelagic marine protozoa), frequently colored red by iron oxides.

The radiolarites constitute stacked decimetric beds, which can form formations several hundred meters thick. They frequently overlie alpine ophiolites.

It is a rock that is used as an ornamental stone under different names : mokaite, different varieties of jasper, etc...