09-25-2012, 10:52 AM
#1
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I have bought a stick of alum. In the package is written that this alum is potassium alum, but I would like to know how to find out if this block is made of potassium alum or ammonium alum.

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 09-25-2012, 10:56 AM
#2
  • beartrap
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Do you have a reason for not believing on what is stated on the package?

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 09-25-2012, 11:06 AM
#3
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(09-25-2012, 10:56 AM)beartrap Wrote: Do you have a reason for not believing on what is stated on the package?

The crystal is not transparent, is white and I think (but I am not sure) that potassium alum crystal is transparent.
Maybe as is a natural crystal, the transparency and texture could be different.

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 09-25-2012, 11:15 AM
#4
  • beartrap
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I can't speak for all alums but I have potassium and it is NOT transparent. I'd google for pics and compare.

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 09-25-2012, 11:22 AM
#5
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You could melt it down and check the boiling point... potassium alum boils at a significantly higher temperature than ammonium alum Tongue

Seriously though, there is little to easily distinguish between the two; both can be clear or whitish while in crystallised form, mostly dependant on the exact conditions it crystallised under. They both work as astringents, and they are both non-toxic.

That said, unless you have reason to believe the label is wrong... well, it probably is potassium alum.

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 09-25-2012, 11:40 AM
#6
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Thank you for the answers.
I suppose you are right and this stick is made of potassium alum. However I would like to know how to distinguish between both kind of crystal.

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 09-25-2012, 03:06 PM
#7
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Just wondering, but is there a reason you want one over the other?

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 09-25-2012, 03:47 PM
#8
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Maybe the OP means aluminum alum rather than ammonium? Alum is a salt and I believe a salt is a metal compound.

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 09-25-2012, 04:19 PM
#9
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(09-25-2012, 03:47 PM)ShadowsDad Wrote: Maybe the OP means aluminum alum rather than ammonium? Alum is a salt and I believe a salt is a metal compound.

I'm thinking this as well. Some people try to avoid aluminum products, like those found in antiperspirants, as there have been some reports linking its use to things like Alzheimers.

EDIT: a quick search reveals that this is an actual ammonia alum.

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 09-25-2012, 06:02 PM
#10
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I stand corrected.

Then I'm at a loss to understand the concern.

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 09-25-2012, 07:06 PM
#11
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I seem to remember reading once that ammonium alum stings more than potassium alum, but I could totally be mistaken (someone please correct me if I am). I have a stick of Crystal brand deodorant, which is listed as ammonium alum, that I used a few times when I was a newbie, and it stung like heck. But that was probably due to my poor technique at the time. I stopped using it after a few days and never bothered trying potassium alum. I'll try the Crystal again tomorrow to see if it stings as much as I remember. If not, it probably was indeed my poor technique.

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 09-25-2012, 07:15 PM
#12
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The ammonium alum is indeed harsher and will give you a greater sting than the potassium varity. The only thing I use my alum block for is the occasional weeper or nick.

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