protogine
/ˈprəʊtə(ʊ)dʒiːn/ /ˈprəʊtə(ʊ)dʒɪn/Geology
noun
A variety of granite occurring in the Alps, containing chlorite and often having a foliated structure resembling that of gneiss, which was formerly thought to be part of the original crust of the earth.
Origin
Early 19th century. From French protogine, irregularly from proto- + ancient Greek γίγνεσθαι (also γίνεσθαι) to be born or produced, intended to express ‘first-produced’, the rock being assumed to be the most ancient of all.