Potassium alum adduct Borax crystal

Do you want to grow a crystal that changes its shape during the process? Perfect! This crystal will start as a normal alum crystal and later take on the cubic shape of borax.

What you need:

Start making the seed solution

  • Dissolving 100g of Potassium alum in 400ml of water
  • Add in 30g of Borax into the Potassium alum solution
  • The solution will appear a lot of precipitate so keep heating and stirring until all the precipitate dissolve (if it can’t dissolve anymore just filter it out)
  • After filter, the solution pour all in a large bottom container and wait for the seed

About the growing process

The seed crystal will appear in a few day and it will look like normal alum seed so be patience. Take the seed out ( remember to wear gloves ) and hang it on to a fishing string, pour the seed solution into a cup and put the seed with the string in it ( don’t let the seed touch the bottom ). When the seed grow slowly the shape will change into cubic shape

A picture that shows the crystal shape change over time
A picture that shows the crystal shape change over time

Note: If you see polycrystals just take the seed out and scrape it off and add a little bit of water into your solution

After the crystal has fully grown you can take it out and put some clear nail polish on it then you can play with it

Final result: