You jest, but there's a ton of people convinced they can use rock alum which is natural and so is better than industrial deodorants which contain aluminium.
I'm similarly puzzled by "uncured bacon" which afaik still uses naturally occurring nitrites. How they're allowed to call it uncured when it's clearly still cured is beyond me.
The rock alum works better, and I don't think you can get it into a different form. The stuff in deodorant is a different aluminium compound.
I can't use those aluminum containing antiperspirants at all -- they violently irritate my eyes if I put them on my skin.