Tag Archives: crystal recipe

Borax Crystal Star of David Holiday Ornament

Borax Crystal Star of David (Anne Helmenstine)

Borax Crystal Star of David – The opalescent effect comes from the colors of the pipe cleaner, showing through the clear crystals. (Anne Helmenstine)

Make a sparkling homemade crystal Star of David to celebrate the holidays! This project is extremely easy, resulting in a keepsake ornament overnight.

Crystal Star of David Materials

  • 2 pipecleaners – use glittery ones to get opalescent colors
  • very hot water
  • borax

Make the Star of David

To form the Star of David, bend a pipe cleaner into an equilateral triangle and twist the ends of the pipe cleaner together to secure the shape. Repeat this with the second pipe cleaner. Overlay the two triangles over each other to make the six-sided star. If you like, you can twist the triangles together a bit to hold them against each other, although the crystals will grow over the shape to hold it into a star anyway.

Grow the Crystal Star

  1. Find a cup or bowl large enough to hold the Star of David. 
  2. In a separate container, mix borax into very hot or boiling water until it stops dissolving. You will know when you have enough borax (saturated solution) because undissolved borax will start to collect at the bottom of the container. 
  3. Pour this solution over the star in your bowl. Try to avoid getting undissolved borax in the container. If you do, it won’t ruin your ornament, but it will compete with the star for crystal growth, so it might slow down your project. If the container is large enough, you can suspend the star into the liquid from a pencil or butter knife to keep the star from touching the sides of the container. The Star of David shown in the photo was simply placed in a jar, so the project works either way. 
  4. Place the container in a place where it won’t be disturbed and allow crystals to grow several hours or overnight. You can loosely cover the container with a paper towel or coffee filter, but make sure not to seal the container so that liquid will be able to evaporate. 
  5. Remove the crystal Star of David from the solution and set it on a paper towel or hang it to dry. You can store the star wrapped in tissue paper to keep it pretty.

More Homemade Crystal Projects

Coral Crystal Garden Using Laundry Bluing

Coral Crystal Garden (Anne Helmenstine)

Coral Crystal Garden (Anne Helmenstine)

The coral crystal garden is a colorful and interesting crystal project that resembles an undersea scene. The crystals look like delicate coral. Fortunately, you don’t need an aquarium or access to the ocean to grow these crystals. This simple project only requires ammonia, salt, and laundry bluing:

Coral Crystal Garden Materials

  • 3 tablespoons household ammonia
  • 3 tablespoons iron(III) ferrocyanide solution (Mrs. Stewarts Laundry Bluing) [buy from Amazon.com]
  • 1 tablespoon table salt
  • food coloring or water soluble markers
  • cardboard or construction paper
  • scissors
  • shallow dish or plate

It is unlikely you’ll find laundry bluing at your local store, but it’s readily available online. A bottle is not too expensive. You can save it for other projects or use it to make your whites whiter (its original intended purpose). If you have access to a chem lab, you can use an aqueous solution of the iron ferrocyanide.

How To Grow the Crystal Garden

  1. Cut out the paper or thin cardboard so that it resembles a coral undersea grotto. Be creative!
  2. Color your scene with water soluble markers or dot it with food coloring. You do not need to completely cover the scene because the crystal growing solution with spread the colors outward.
  3. Prop up the scene on a plate or shallow dish.
  4. Mix together the ammonia, bluing (iron ferrocyanide solution) and salt.
  5. Dribble some of the solution onto the paper scene. Pour the remainder into the bottom of the dish so that the paper can absorb it.
  6. Set the undersea scene somewhere that it won’t get bumped or disturbed. The crystals will grow over the next several hours. Expect your crystal scene to be complete overnight or within 1-2 days. The length of time depends on temperature and humidity. The solution will evaporate more quickly when it is warm and dry. If you like, you can add more crystal growing solution to the base of the scene.

Caring for the Crystals

You can keep the crystals when they are done growing, but expect them to lose some structure over time. Fragile crystals may break off or the salts may re-dissolve under high humidity.

Related Crystal Projects

Watch a Time Lapse Video of a Coral Crystal Garden Growing

Grow Natural Bright Red Potassium Ferricyanide Crystals

Potassium ferricyanide is also called "red prussiate". (Paul's Lab, Flickr)

Potassium ferricyanide is also called “red prussiate”. (Paul’s Lab, Flickr)

Grow natural red monoclinic crystals without using any dye. The chemical used for the crystals is potassium ferricyanide (K3Fe(CN)6) or ‘Red Prussiate of Potash’. It has the C-N group, which is the cyanide, but it’s bound in the crystal and won’t hurt you.


93 g potassium ferricyanide
200 ml warm water


  1. Dissolve 93 grams of potassium ferricyanide and 200 ml warm water into a clear container. If you can’t measure the powder or water, stir in enough potassium ferricyanide that it stops dissolving in the warm water, making a saturated solution.
  2. Now, you can simply wait for crystals to grow or you can try to grow a single monoclinic red crystal. To do this, you need a seed crystal.
  3. To get a seed crystal, pour a few drops of your solution onto a plate or saucer. Allow this liquid to evaporate to form seed crystals. Select the best crystal and place it in a clean container with the rest of the solution.
  4. Cover the container with a paper towel or coffee filter to keep it clean, but permit evaporation.
  5. Leave your solution undisturbed, but check on it daily to observe crystal growth.
  6. Once the crystals have reached the desired size (a week or two), remove the crystal and allow it to dry on a paper towel.
  7. Store your crystal wrapped in a piece of tissue.

Tips for Success

The IUPAC name for potassium ferricyanide is potassium hexacyanoferrate(III). (Maxim Bilovitskiy)

The IUPAC name for potassium ferricyanide is potassium hexacyanoferrate(III). (Maxim Bilovitskiy)

If you are having trouble getting all of the solid to dissolve, try using hotter water. If the solid still won’t dissolve, let the solution to settle out, then use only the clear portion for growing crystals. This solution may not be saturated initially, but as the water evaporates, it will become more concentrated.

You can control where the crystals grow. If you have solids in your starting solution, the crystals will form (nucleate) around these particles. This is why a seed crystal helps with growing a large single crystal. It’s also why a solution with undissolved particles develops into a mass of small crystals.

You can buy potassium ferricyanide at Amazon and other places as a photography chemical.

While you’re waiting for the crystals to grow, there is another project you can try with your leftover potassium ferricyanide: burning it together with potassium chlorate. Now, it turns out, the rate at which the mixture burns can be predicted based on its color. It’s a pretty awesome pyro project.

Grow Blue-Green Copper Acetate Crystals

Copper Acetate Crystals

Copper Acetate Crystals (Choba Poncho, public domain)

It’s easy to grow large naturally blue-green monoclinic crystals of copper acetate monohydrate [Cu(CH3COO)2┬ĚH2O].


  • copper acetate monohydrate
  • hot water
  • acetic acid or vinegar (if necessary)


  1. Dissolve 20 grams of copper acetate monohydrate in 200 ml of hot water. If you don’t have a scale, don’t despair. Dissolve the copper acetate in warm water to create a saturated solution. You’ll know you have enough of the powder added when it stops dissolving in the liquid.
  2. If you see a scum of undissolved material, stir in a couple of drops of acetic acid (vinegar).
  3. Place the container in an undisturbed location to allow crystal to grow.
  4. Blue-green crystals should start to appear within a couple of days. You can allow them to grow on their own or can you can select one perfect crystal to use as a seed crystal to grow larger crystals.
  5. If you wish to grow a large single crystal, place the seed crystal in a new container and add the copper acetate solution from the old container.
  6. When you are pleased with the crystal, remove it and place it on a paper towel to dry.

You can also grow copper acetate crystals using a penny:

Grow Table Salt or Sodium Chloride Crystals

Table Salt Crystals (Choba Poncho)

Table Salt Crystals (Choba Poncho)

Table salt or sodium chloride crystals are among the easiest crystals to grow. The materials are easy to find and inexpensive, plus the crystals are non-toxic.

Crystal Growing Materials

  • table salt – sodium chloride – NaCl
  • water
  • clean clear container
  • piece of cardboard (optional)
  • string
  • pencil or butter knife (optional)

Salt Crystal Step-By-Step

  1. First you need to prepare a saturated salt solution. Stir salt into boiling hot water until no more salt will dissolve. Salt may settle out at the bottom of the liquid. This is fine – just make sure none of the undissolved salt gets into your crystal-growing container. Be sure the water is as close to boiling as possible. Hot tap water is not sufficient for making the solution. If you want colored crystals, you can add some food coloring to this solution.
  2. If you want crystals quickly, you can soak a piece of cardboard in this supersaturated salt solution. Once it is soggy, place it on a plate or pan and set it in a warm and sunny location to dry out. Numerous small salt crystals will form over the span of a couple of hours.
  3. If you want a mass of crystals, you can simply pour the saturated salt solution into a clear container and let it slowly evaporate. Crystals will grow on the sides of the container.
  4. If you are trying to form a larger, perfect cubic crystal, you will want to make a seed crystal. One way to get a seed crystal is to pour a small amount of saturated salt solution onto a saucer or watch glass. As the liquid evaporates, crystals will start to form. Select a single square crystal and remove it from the dish.
  5. To grow a big crystal from a seed crystal, carefully pour the supersaturated salt solution into a clean container (so no undissolved salt gets in), allow the solution to cool, then hang the seed crystal in the solution from a pencil or knife placed across the top of the container. The solution needs to be saturated and cooled so that it won’t dissolve your seed crystal. You could cover the container with a coffee filter or paper towel to keep out dust, yet permit evaporation.
  6. Set the container in a location where it can remain undisturbed. You are more likely to get a perfect crystal instead of a mass of crystals if you allow the crystal to grow slowly (cooler temperature, shaded location) in a place free of vibrations.

Crystal Growing Tips

  • Experiment with different types of table salt. Try iodized salt, uniodized salt, sea salt, or even salt substitutes. Try using different types of water, such as tap water compared with distilled water. See if there is any difference in the appearance of the crystals.
  • If you are trying for the ‘perfect crystal’ use uniodized salt and distilled water. Impurities in either the salt or water can aid dislocation, where new crystals don’t stack perfectly on top of previous crystals.

Learn More

Charcoal Crystal Garden
Troubleshoot Common Crystal Growing Problems