Min. [mod. (Fr. alunogène 1832) f. Fr. alun alum + -GEN, taken as = producing.] A mineral, also called Keramohalite, a hydrous sulphate of alumina, occurring as a feathery efflorescence, to which, among other substances, the names hair-salt and feather-alum are applied. (Halotrichite, sometimes used as a synonym, is applied by Dana to a distinct mineral.)
1868. Dana, Min., 650. This species was made known by Beudant, and by him first named Alunogen.
1868. Watts, Dict. Chem., V. 579. The normal or neutral sulphate [of aluminium] Al2(SO4)3 … is known mineralogically as alunogen, hair-salt, feather-alum, and halotrichite.
1878. Lawrence, Cotta’s Rocks Class., 43. Alunogen is sometimes the product of volcanic action, sometimes a result of the decomposition of pyrites in coal districts.
