Category Archives: Crystals

Grow your own crystals with these easy recipes. Learn about crystal structures and how crystals are classified.

Borax Crystal Heart Science Project

Borax Crystal Heart

Borax Crystal Heart

Grow borax crystals overnight to make a beautiful sparkling crystal heart. Use the borax crystal heart as a decoration or simply grow it as a fun crystal project.

Borax Crystal Heart Materials

  • borax
  • water
  • pipecleaner

Make a Borax Crystal Heart

  1. Shape the pipecleaner like a heart. It’s fine to have a ‘stem’ at the bottom of the heart, since this will give you a way to suspend the heart in the crystal growing solution. You can always clip it later with scissors or wire cutters.
  2. Prepare the crystal growing solution by stirring borax into boiling hot water until it stops dissolving. You can tell you have enough borax if a little powder starts to accumulate in the bottom of the container.
  3. Add food coloring, if desired. Alternatively, if you want a colored heart you can simply use colored pipecleaners.
  4. Place your heart shape into a container. It’s best if the heart doesn’t touch the sides or bottom of the container, which you can achieve by hanging the heart from a pencil or butter knife. However, you’ll get decent results just setting the heart into the container. 
  5. Pour the borax crystal solution into the container, being certain all of the heart is covered. Try to avoid getting any undissolved solid into this container.
  6. Allow the crystals to grow on the heart for several hours or overnight. When you are satisfied with the crystals on the heart, remove it from the crystal solution and allow it to dry. You can hang the heart as a decoration. The crystal heart may be stored wrapped in tissue paper.

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

How to Grow Calcium Carbonate Crystals (Aragonite)

Calcium Carbonate Crystals (Aragonite) photo credit: Christophe Delaere

Calcium Carbonate Crystals (Aragonite) photo credit: Christophe Delaere

Calcium carbonate crystals can take any of a number of forms. You can grow your own crystals that will resemble either the clear needle-like calcium carbonate prisms found naturally around hot springs or the delicate, lace-like branching structures found in caves and mines (cave flowers). The mineral CaCO3 is known as aragonite when it occurs naturally. Calcium carbonate also takes other forms as vaterite and calcite crystals, but you’d need to control the pH (acidity of the solution) to see these forms.

Materials for Calcium Carbonate Crystals

This is a super-simple project, since you only need two materials!

  • dolomite rocks
  • household vinegar (dilute acetic acid)

If you haven’t collected any dolomite rocks or can’t find them, dolomite is also commonly sold in garden stores in powdered form. You can also get dolomite at Amazon. You can use powdered dolomite just fine, but you’ll want to provide a growing surface to support crystal growth. An old piece of kitchen sponge works great since it offers a large surface area. If you want a more natural-looking crystal, you could grow the crystals on a rock.

Let’s Grow Crystals!

Aragonite Crystals (photo credit: Mike Beauregard)

Aragonite Crystals (photo credit: Mike Beauregard)

If you have a dolomite rock, rinse it off to remove any dirt and debris and let it dry.

Place your dolomite rock in a container. Try to choose one that’s just a bit larger than the rock, to reduce the amount of vinegar you need. If you’re using powder, place your growing rock or piece of sponge in a container and heap the powder on top of it.

Pour vinegar around the rock or sponge, but don’t completely cover the surface. You want to leave exposed space at the top.

Set the container someplace where it won’t be disturbed. Be patient. In about a day, the calcium carbonate crystals will start to grow at the liquid line.

When you’re pleased with the crystal growth (usually 5 days to 2 weeks) you can remove the crystals to observe or display them. Alternatively, you could just wait for all the vinegar to evaporate.

If you used pure calcium carbonate, your crystals would be clear or white. Using dolomite as the source, your crystals will be colored. The color depends on other compounds found in the mineral. Brown, green, and gray are common colors.

Dolomite, Aragonite, and More

Aragonite Crystal Cluster - Aragonite from Tazouta Mine, Sefrou, Morocco (photo credit: Kevin Walsh)

Aragonite Crystal Cluster – Aragonite from Tazouta Mine, Sefrou, Morocco (photo credit: Kevin Walsh)

Dolomite is a sedimentary rock made of calcium carbonate. Aragonite is a crystalline form of calcium carbonate.

Calcium carbonate also takes other forms. It’s commonly found in biological systems, especially in the ocean. Sea shells and pearls also consist of this mineral.

Time Lapse Video of Calcium Carbonate Crystal Growth

Would you like to see what to expect? Here’s a time lapse video of calcium carbonate crystals growing from a “popcorn” rock:

Borax Crystal Flowers for a Spring or Easter Bouquet

Grow pretty borax crystal flowers. These colorful flowers only take a few minutes to set up and a couple of hours to grow. It’s a fun project for kids and a great way to decorate with flowers that won’t ever wilt.

Borax Crystal Flower Materials

Spring Crystal Flowers

Spring Crystal Flowers (pipecleaners and borax)

Now, I recommend borax because it’s super-easy to grow the crystals, but if you can’t get hold of this chemical, you can use sugar, Epsom salts, alum, or table salt. The basic process is the same, no matter which substance you use. The difference is the size and shape of the crystals and how long it takes for them to form. Don’t be afraid to experiment!

  • colored pipecleaners (chenille craft sticks)
  • borax (or whatever you’re using)
  • water
  • tall glass
  • pencil
  • scissors or wire snips

Grow Crystal Flowers

  • The first step is to form the flowers. You can be as creative as you like, so long as the finished flower fits inside the glass, which will hold your crystal solution. I made the flowers shown here by spiraling pipecleaners around a pencil. Then I twisted one end of the “flower” to a green pipecleaner to form a stem. I made a couple of flowers this way and even a leaf. Use the scissors or wire snips to cut away excess flower-colored pipecleaner, but keep the green stems nice and long.
  • Turn your “bouquet” upside down and put it in the glass. Wrap the stem around the pencil and adjust the pipecleaner flowers so they don’t touch the bottom of the glass. It’s also best if they don’t touch the sides of the glass or each other, because they’ll stick together as crystals grow.
  • Remove the flowers/pencil from the glass.
  • Next, make the crystal growing solution. To do this, boil enough water to fill your glass. I used a tea kettle, but you can microwave the water in a microwave-safe bowl or run water through your coffee maker, etc.
  • Pour the water into a bowl or large cup and stir in borax (or whatever you’re using) until no more dissolves. You can tell you’ve reached the saturation point when you have undissolved solids at the bottom of your container, no matter how much you stir. This is the crystal growing solution.
  • Pour the solution into your glass, but avoid pouring in the undissolved solid. It’s no big deal if a little bit gets into the glass, but any solids will compete with your flowers for crystals.
  • Add the flowers to the glass of solution. Place the glass somewhere it won’t get spilled or disturbed.
  • Crystals will start growing within half an hour or so. It’s up to you how long to let them grow. If you want a light dusting of crystals, remove the flowers from the solution after an hour or two. For as many crystals as possible, leave the flowers in the liquid overnight.
  • Remove your flowers. Either hang dry them or set them on a paper towel. When they are dry, place them in a vase or use them as a decoration.

More Crystal Flowers

Another simple crystal flower to make using pipecleaners is a crystal rose. But, you don’t have to use pipecleaners. It’s also easy to grow crystals on a real flower!

How To Make Glow in the Dark Crystals

This quartz crystal glows in the dark. It's easy to replicate the technique to make your own crystals and gems glow.

This quartz crystal glows in the dark. It’s easy to replicate the technique to make your own crystals and gems glow.

You can make any clear or translucent crystal glow in the dark! Here’s how I made a genuine quartz crystal glow. You can apply this method to make other natural gemstones, glass, or plastic items glow. If you’d rather grow crystals that glow in the dark, try my glowing alum crystals tutorial. If you want to treat a crystal you already have, read on…

Glow in the Dark Crystal Materials

Technically all you need is a crystal and any phosphorescent paint, but if you want the crystal to glow very brightly, glow for a long time, and resist water and wear, you need three materials.

  • translucent or transparent crystal or gem
  • phosphorescent paint
  • lacquer (acrylic or polyurethane)
  • black light (not essential, but very helpful)
The glow treatment on this quartz crystal is invisible under normal light.

The glow treatment on this quartz crystal is invisible under normal light.

I used acrylic phosphorescent paint by Glow, Inc. and Sculpey glaze, but there are other products out there.

It is important that you choose phosphorescent (which really glows in the dark) and not fluorescent (glows for fractions of a second) paint. Your color choice is somewhat important. Strontium aluminate pigments (the awesome ones) glow most brightly in green and aqua. Blue is quite nice, but a bit darker. Violet and white are beautiful, but not nearly as bright and don’t glow as long. Red and orange are improved versions of zinc sulfide and fade very quickly.

Varathane and Future are good sealant choices. They dry clear and are durable. Clear nail polish is not recommended because it has the reputation of yellowing over time and reacting with some polymers. Some clear polishes may be fine, but the other options don’t cost more, so why risk it?

How To Make the Crystal Glow

  1. If you’re like me and using a pretty crystal you found in the ground, your first step will be to clean the stone and let it dry completely. If you think your stone is already clean, wipe it down anyway, to remove any residue.
  2. Identify the part of the crystal you want to glow. You may be thinking you need to treat the whole crystal in order to make it glow. Nope. You simply need to make part of the stone phosphorescent. What’s important is that this part of the crystal can receive light. For a piece of quartz, rose quartz, pale amethyst, citrine, cubic zirconia, acrylic, etc. this can be any part of the stone. Usually you’ll treat the back of the stone, causing it to appear to glow from within. You could also treat the top and/or bottom of the crystal. It’s up to you.
  3. Use a small paintbrush to apply a thick, even layer of phosphorescent paint to the selected surface. Again, don’t paint the whole crystal unless you want to hide the natural beauty of the stone. You don’t want to do that, right?
  4. Let the paint dry completely. I allowed half an hour.
  5. Apply a second coat. If you have a black light, turn it on so you can see how you’re doing and to identify areas that need more phosphorescent pigment.
  6. Again, let the treatment dry. Now, you should have a nice glow in the dark crystal. Either expose it to black light or else hold it out in the sun or under a bright indoor light or your cellphone flashlight to charge the pigment. Turn out the lights and examine your work.
  7. If you’re pleased with the glow, you can continue to the next step, which is sealing the stone. Otherwise, you may wish to apply another 1-2 coats of paint.
  8. Finally, you should seal the stone. There are 2 reasons for this. The first and most important reason is that modern phosphorescent pigments are destroyed when they come in contact with water. Theoretically pigment in an acrylic paint is already encapsulated and protected, but it’s better to be safe than sorry, or you might have selected a solvent-based paint that won’t protect your pigment at all. The second reason is because the phosphorescent particles need to be large to produce a good glow. This makes the painted surface gritty. Coating the crystal smooths out the surface so the treated area will look and feel natural. Also, I think the lacquer helps prevent chipping and wear of the coating.
  9. Use a paintbrush to apply a thin, even coating of sealant to the treated part of the stone. I stick with one coat and don’t paint the untreated parts of the crystal, but you can coat everything, if that’s your thing. Allow the crystal to dry completely. No touchy! You’ll leave a fingerprint in the sealant, which probably isn’t what you want.

Now comes the fun part. Enjoy your creation! You can leave it on a desk and enjoy its glow whenever the lights go out, place it on a bathroom counter as a night light, or wire-wrap it for a pendant or a keychain.

What are you going to make?

Grow Crystals on a Starfish

Grow crystals on a starfish or a shell for a pretty beach-themed decoration.

Grow crystals on a starfish or a shell for a pretty beach-themed decoration.

Grow crystals on a starfish to make a sparkling crystal starfish ornament or decoration.

Crystal Starfish Materials

You can grow any crystal solution on the starfish, including borax, salt, alum, Epsom salt and sugar. Borax is nice because the crystals grow overnight and add a dainty sparkly appearance to the starfish. Also, these crystals survive storage and packing between holidays quite well.

  • small dried starfish
  • string
  • jar big enough to hold the starfish
  • string
  • hot water
  • borax (e.g., 20 Mule Team Borax

How To Grow Crystals on a Starfish

  1. Tie a string or piece of nylon fishing line to the starfish. Make certain the starfish can hang in the jar without touching the side or bottom. You can wrap the string around a pencil or butter knife to control its length. Remove the starfish from the container.
  2. Mix a solution of very hot or boiling water and borax. Keep stirring in borax until it stops dissolving. This will be when a small amount of solid material remains in the bottom of the container.
  3. Pour this solution into the jar.
  4. Suspend the starfish in the liquid. Make certain it is submerged, but not touching the jar. Allow the crystals to grow for several hours or overnight.
  5. Remove the crystallized starfish from the liquid and hang it to allow it to dry. That’s it! You can use it as a holiday ornament or other decoration.
  6. You can store the starfish by wrapping it gently in tissue paper to protect it from dust and humidity.

Tips and Tricks

  • Borax allows the natural color of the starfish to show. However, if you want to add color, you can. Simply add a small amount of food coloring when you mix the borax and water. The food coloring does not color the crystals, but it will dye the starfish.
  • Try growing crystals on small shells. You’ll have the best success with porous shells because they provide places for the crystals to attach and grow.

More Projects Using Borax

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