Crystal Seashells

Combine the excitement of the beach and the joy of science together with these amazing crystal seashells!

Do not worry if the beach is out of reach, local art stores tend to carry an assortment of shells and ocean decor.

  1. Ages: 5 - 11

  2. 30 minutes - 1 hour

  3. A little messy

  4. Grownup needed

Step-by-step tutorial

  • Warning

    Borax (sodium tetraborate) is a naturally-occurring mineral salt commonly used as a laundry booster or cleaner. As with any other cleaning product, it should be kept away from children not under direct supervision of an adult. Do not allow children to ingest Borax. If consumed, contact a poison control center immediately. Wash hands after play, as prolonged skin exposure may cause irritation.

  • Step 1

    Boil the water. Have an adult help or carefully supervise any heating necessary for this project.

    Photo reference of how to complete step 1

  • Step 2

    Add the borax 1 tablespoon at a time to the water and stir. After you have finished adding in all of the borax, you can add a couple drops of food coloring to give your crystals a subtle hue.

    Photo reference of how to complete step 2

  • Step 3

    Arrange your shells in a flat layer in the glass container. (This container allows the solution to cool slowly, a necessary component to grow the crystals).

    Photo reference of how to complete step 3

  • Step 4

    Pour the borax solution over the shells making sure that they are all completely covered. The blue dye made our shells look like they were back in the ocean!

    Photo reference of how to complete step 4

  • Step 5

    Place the container in a safe, unbothered location and wait for your crystals form! After 24 hours, you can remove the shells from the solution and place them on paper towels to dry.

    Photo reference of how to complete step 5

  • Step 6

    Enjoy your new crystal shells! You can also try this experiment with dried starfish to create beautiful ocean decoration. 

    Photo reference of how to complete step 6

  • Learn moreMagnifying graphic

    Water becomes more soluble the warmer it gets, so when it is heated up, it can dissolve more substance than it can at room temperature. The borax solution that you mixed together is a supersaturated solution. This means that there is more borax dissolved in the water than there normally would be at room temperature. Once the supersaturated borax solution starts to cool, the water molecules contract and there becomes less room to keep all of the borax dissolved in the water. These excess borax molecules begin to seek out a more stable place to rest, and quickly crystallize on the closest solid surfaces - in this case, your seashells! You can seed crystals in a supersaturated, cooling solution by dropping in any solid surface. In fact, rock candy is made by making a supersaturated solution of sugar and food coloring, and seeding sugar crystallization by dropping in a stick. Enjoy!

Share what you made & tag us at!