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How To Grow Your Own Crystals: It All Starts With A Seed

If you were to look on my desk, in my room or though my backpack, sure enough you would find some type of crystal. From the colors, to the geometric shaping, they are visual candy that I just can’t seem to get enough of. There are a ton of different crystals that exist, and Brigette’s crystal post earlier in the week gave some great suggestions on ways to incorporate them into your life. In addition to bringing you ways to use them, I wanted to share with you all a way to actually make some crystals of your own! You can make all sorts of homemade crystals, but a lot of them involve chemicals that you might not have access to or have a hard time finding. An easy kind you can make yourself are alum crystals.


Alum is a type of salt that you can readily find in the spice isle of many grocery stores. It’s a little coarser than table salt, and has more of a distinct smell. It’s normally used for pickling different types of vegetables, but it’s also the perfect ingredient for making your own crystals. Like with anything that grows, a seed is required to start the process. In this post today, I am going to share with you how to make seed crystals, which eventually will turn into a large, clear alum crystal!

alum and water

All you need are a few things to start the process:

2 tbsp Alum

1/2 cup hot tap water

glass jar

Fishing wire or sewing thread


pouring in

Pour the alum and hot tap water into a glass jar.

stirring alum and water

Stir the mixture until the water is saturated and foggy.

water and alum

Put the jar in an undisturbed place, and place a coffee filter over it. Within a few hours, you will start to see little seed crystals forming on the sides and bottom of the jar. I let my jar sit overnight.

crystals in jar

In the morning, I took off the coffee filter and carefully poured out the excess alum solution. I was amazed at how many little crystals had formed!

crystals on wood

These little guys can be used as seed crystals to form a larger crystal. If you are happy with tiny crystals, feel free to stop here! If you want to try and grow a bigger one, the next step is to find one of the largest ones out of the bunch you have. Tweezers come in handy here!

fishing wire

Once you have selected one, take some fishing line and tie a knot around the crystal. If you are having a difficult time with the nylon fishing wire, you can try using some sewing thread. Tie the other end to an object that you can use as an anchor. (I used a stick but you can also use a pen, Popsicle stick, ruler, etc…) Fill up another glass jar with a new batch of alum solution, and carefully place the crystal into the jar. The wire/ string should be long enough to have the little crystal submerged in water, but not touching the bottom. The alum in the solution will start moving towards the little crystal to help it grow!

twig in formula

I’m going to let my crystal sit for a few days in the solution and see what happens. If all goes well, I should be left with a bigger, beautiful alum crystal!

Have you all ever tried growing crystals? Please share!

More DIY projects from the BLDG 25 Blog.

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Lise -June 26, 2014, 9:17AM

I did this at school! You shouldn’t let the crystals sit in the solution for more than a day, they will disappear! You have to make a new solution every day. I made the same mistake when I made crystals :)
Oh, and make sure to put some kind of hairspray or fixative on them when you’re done! Otherwise they’ll turn back into salt.

fp jana -June 26, 2014, 9:28AM

Thank you for the tip, Lise!

i.s. -June 26, 2014, 2:23PM
jodie -June 26, 2014, 7:36PM

i remember doing this in kindergarden for christmas! we coiled green pipe cleaners to look like trees and dipped them into the solution to make ornaments. they were super pretty. i wondered how we made them time to time and now i know! nostalgia.

Juliette Laura -June 27, 2014, 1:28AM

Ohhh so fun!!! Definitely want to try this! Can’t wait to see the results of your big crystal!

Leo Tyler NW6 -June 27, 2014, 3:54AM

This is so cool. Why I never did it at school? It is interesting and I think that my kids will be so into it. We will try the project this weekend and I will come back to share the result at the beginning of the new week. Thank you so much for sharing this idea and making the tutorial.

isabelle -June 27, 2014, 4:31AM

do you think you would be able to add food coloring into the solution to get a colored crystal?

Elizabeth -June 29, 2014, 10:48AM

I tried this as a school project (…years ago). My dad knocked the jar over and so helpfully topped it up “with some more water” so the little crystal that had been so happily growing not so happily dissolved again.

Now feel inspired to try again – a fun summer project for my little niece and myself – thanks for reminding me.

Dinha Puffy -June 29, 2014, 7:27PM

Omg, can i play with salt and make my own crystal?
This is so lovely, i wanna look for this in my city, thaaaank you so much :)
kiss from Puffy Plaft Zoom

Jade -July 15, 2014, 4:03PM

This tutorial is so neat! I will definitely be trying it soon. My only question is what happens to he thread once the crystal grows?

Stay lovely <3

Marce -September 21, 2014, 1:16PM

I tried this yesterday and looked at it this morning and nothing had formed. It’s just a clear liquid. For an easy DIY I still managed to mess up somehow, any help? I was looking forward to making crystals. ):

Virginia -September 26, 2014, 2:05PM

My grocery carries sea salt, kosher salt and pickling salt. Would either of these be the proper salt?

Jo Moxie -November 27, 2014, 12:02PM

This is awesome!
How long does the crystal last? Is it strong enough to use/carry around/wear/hang?


sarah p. -May 6, 2015, 9:19AM

I just tried this but i added purple food coloring. Turned out beautiful. Thanks for posting this tutorial.

Angela -July 23, 2015, 11:57PM

Are you able to add food coloring for different color crystals?? Or will that affect it

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