Natural Mineral Deodorant and After Shave. An ultimate ingenious life-hack product and the best kept secret: natural alum stone! Bloc Hyalin, unlike other stones, has always benefited from a long and complex process of purification. Alum potassium premium 100% natural, of which Bloc Hyalin is made, is not mixed with any chemical or synthetic product. This natural alum block has strong antibacterial properties, so it can be used as a deodorant, or to prevent irritation after shaving or waxing, works on spots too! As a deodorant it’s totally odorless, and leaves your clothes unmarked.