radiolarite
/ˌreɪdɪə(ʊ)ˈlɛːrʌɪt/Geology
noun
A type of hard, homogeneous, fine-grained siliceous sedimentary rock formed mainly from the skeletal remains of radiolarians. Also: any sedimentary rock formed mainly from radiolarians; radiolarian earth.
Origin
Early 20th century. From French radiolarite from scientific Latin Radiolaria + French -ite.