Disseminated and faultbound autohydrothermal ferroan saponite in Late Paleozoic andesites of the Saar-Nahe Basin, SW Germany: Implications for the economic geology of intermediate (sub)volcanic rocks

► Saponitization a measure of rock strength in search or construction raw material. ► Saponite/nontronite ratio an ore guide to Cu-Au ore deposits. ► Saponitization is an autohydrothermal alteration under epithermal conditions.