The Féret Parfumeur Bloc Hyalin is a 100% natural potassium alum stone, renowned as the purest alum stone in the world.
First brand in the world registered in France and abroad, The Hyaline Bloc has often been imitated, never equalled since its creation, with its authenticity confirmed by its slightly translucent, marbled appearance and the “potassium alum” listing in the ingredients. Bloc Hyalin combines astringent, antiseptic, and antiperspirant properties: it regulates perspiration without clogging pores, neutralizes bacteria that cause odor, protects skin from friction-related injuries, and soothes micro-cuts or post-shaving irritation. Trusted for over a century, it remains a timeless choice for natural, effective care.