roche-alum
Roche" al`um. (Chem.) Defn: A kind of alum occuring in small fragments; -- so called from Rocca, in Syria, whence alum is said to have been obtained; -- also called rock alum.
Roche" al`um. (Chem.) Defn: A kind of alum occuring in small fragments; -- so called from Rocca, in Syria, whence alum is said to have been obtained; -- also called rock alum.