Corsi Collection of Decorative Stones

Class VI
Alumstone (Pietra alluminosa)

564. (140) Its colour is of dirty yellowish white and it has the look of hardened clay; it is medium-hard, without sheen, does not effervesce in acids, and takes little polish. It is found in Tolfa in the Stato Romano from whence the best natural alum is extracted. In Rome it is (very common).