Updated: Nov 13, 2018
Alum is a sulphate salt ( KAl(SO4)2·12H2O ) . It has been used for centuries in water purification, it’s used in pickling to keep your pickles crisp and crunchy.
In this tutorial, I am going to show you how to make crystals from Alum. Creating crystals out of alum is an easy process that can be completed using materials from home and the grocery store. It can teach children about science, or can be used to create decorations, paperweights, or garden decorations.
Use your own creativity to make different types of crystal for different purpose. In the beginning, I made a crystal flower vase, then I made few more crystals for home decoration.
Step 1: Materials Required
1. Alum Powder ( Amazon )
2. Glass Jar ( Amazon )
3. Super Glue ( Amazon )
5. Food Coloring ( Amazon )
Step 2: Make Alum Powder
This step is optional if you have powdered alum already.Alum powder can be found at local grocery store / drug stores or ordered online. In my location, I could not find the alum powder. So, I purchased the bigger size alums from the local store.
First make smaller size alums by using a hammer.
Then crushed it in to powder form by using a rammer.
Safety : Alum is non-toxic. Alum solutions can cause eye irritation. Wear goggles or safety glasses when working with the solution.
Step 3: Tie a Wire
Tie a wire ( I used copper wire ) at the neck of the jar as shown in the picture.
It is not mandatory to used a copper wire, you may use a nylon string which can bear load of glass jar along with the crystal.
Step 4: Stick the Alum Powder
First clean the glass jar and dry it. Pour some super glue onto jar surface and use a paintbrush to coat it all around. You only need a thin layer of glue; just enough for the alum to stick to the surface.
Stick the alum by rolling the glass jar over the alum powder.The powdered alum will serve as a starting point for a crystal to grow.
Then Leave it for drying.
Step 5: Make a Saturated Alum Solution
In order to start growing the crystal, you need to make a solution of hot water and alum.The crystal formation will be better when the solution is saturated.Normally alum dissolve faster in hot water than in cold water. So we have to prepare the hot water first.
Take enough water so that the glass jar will be completely immersed in side it. Then boil the water and add alum powder in to it. Continue adding and stirring until the powder no longer dissolves.The water is now saturated with alum.
Step 6: Add Food Coloring
Now transfer the hot alum solution in to a big heat safe container.The container needs to be large enough for the glass jar to be completely immersed in side it.
Add some food coloring in to the hot saturated solution of alum.Choose the color according to your own choice.
Then stir it until the whole solution becomes colorful.
Note :Food color come in powder as well as liquid form, but for me the powder worked good.
Step 7: Submersed the Jar in the Alum Solution
Make sure the solution is cooled to room temperature before placing the glass jar into it. If the water is warm, the alum powder on jar surface will dissolve. In my first attempt,I was failed to make the crystal because of this reason only.
Gently submersed the glass jar into the container and make sure it is completely covered by the solution.
Store the jar in a place that it will remain undisturbed. If the jar gets bumped or moved around, the crystals will not grow.Leave it for at least 24 hours.
Note : Keep the container in a cool place, so that the alum on the glass surface will not dissolve.
Step 8: Remove the Crystal
Check your alum solution after 24 hours, you’ll find crystals formed at the neck of the glass jar.
Now you can pull it out carefully by holding the wire hanger.
Pull the crystal slowly, otherwise it may break.
Step 9: Trim the Hanger Wire
Carefully cut the wire as close to the crystals as possible.I used a nipper to cut the wire.
Step 10: Use the Crystal As Flower Vase
Pour some water in to the crystal jar.
Place the flower stems inside the water.
Arrange the flower to give a decorative look.
Step 11: Make Variety of Crystals
Finally you get to know the procedure for making alum crystals. Now it is time for you make your favorite alum crystals.I made a variety of crystals for home decoration. You can see the above images.
the mentioned link below is a video tutorial of the Article.
For full step by step guide, you can visit my Instructables also.