Alum and us
We have been processing alum stone and its derivatives for over 50 years: Osma Manufacturing is the only French manufacturer of natural alum stone. We are a master alum maker.
A natural ingredient with many virtues
Alum stone is a natural stone, similar to crystal, translucent and odorless. It has been mined since ancient times in alunite deposits, first in Syria and today around the world.