Australia's Science Forum

Hi everyone,

I need help please on Alum crystals. On most web sites they say you can buy Alum from your spice section in the supermarket or chemist.
But is it the same as using Aluminium Potassium Sulfate? (Potash Alum)

Thanks
Julz

I use Aluminium Potassium Sulfate (Potash Alum) when ever i am making crystal that ask for Alum. Our teachers said it is the same. They make great crystals, just make sure that they heat the solution first. Also if you are making crystal with this add some food colouring to make different colours and the Junior classes love this.
KIM

Thanks Kim,

I thought it was and I haven't tried the food colouring yet.
It makes a nice change from Copper Sulfate Crystals.

Julz

Yes.. remember that the alum with blue food colouring will also be a different shape from the Cu SO[sub]4[/sub] crystals though. And a word in the teachers ear.. to explain to the students if using food colouring... that thie alum crystal is naturally CLEAR.

Hi everyone
Can I get a copy of your recipe to make crystals.

Thank You
Mary

Hi Mary,

I usually make up a Super Saturated solution of Alum and have them cool very slowly..

This makes for some good tetrahedral shapes and sometimes Rhombic.

See you soon,

Robb.....

Hi, here in sleepy hollow (Adelaide) we have a State crystal growing competition each year. The best way to grow them is in the incubator at around 30 degrees. A good Alum crystal is tetrahedral in shape and Crystal Clear. And yes, our kids won First Prize.

Hi there Mary,
Post me your email address and I will send you our file with different crystals to grow.
KIMMY