'Crystal' deodorant bad for you???

As we know aluminum has bad review when it comes to cancer and illnesses. There was a report on TV the other night (I did not see it my friend did) saying that  the ‘Crystal’ brand deodorant that everybody buys thinking it is a natural product contains aluminum that is bad for you. I was skeptical at first thinking it was a biased report for the traditional deodorant and antiperspirant companies.

I did a small research and it looks as if there are two types of rock deodorants (alum deodorants): the natural alum deodorant and the synthetic one. The natural one contains potassium alum and the synthetic contains ammonium alum. There is no way to tell the difference just by looking at it. The Crystal brand doesn’t make a difference between the two types threfore I assume it is ammonium alum otherwise they would be glad to say it is potassium alum. Has anybody came across this information. The ‘Crystal’ business is booming and may be misleading everybody??? They say there is no Aluminum Chlorohydrate that they use in regular deodorants which I believe is true. But do they sell the synthetic or natural rock? They don't say...