How to Grow Crystals

How to Grow CrystalsDo you want to learn how to grow crystals? Growing crystals is a fun and educational science project. You learn about solubility and how molecules interact and stack together, plus you get a beautiful souvenir to keep for your efforts. This is a collection of crystal growing projects you can do with materials you either have at home or can get at a store or online. You can make crystals by dissolving chemicals in water or by melting solids and crystallizing them as they cool.

Tips to Make Crystals

To grow crystals from common chemicals that dissolve in water, the general steps you take are:

  • Dissolve as much solid in hot to boiling water as you can. This makes a saturated solution.
  • Control the rate of evaporation and cooling to control the size and shape of the crystals. In other words, if you refrigerate a solution for quick cooling, you’ll usually get smaller crystals than if you slowly cool the solution. If you place the solution in a sunny window, the solution will evaporate more quickly than if you place it on a shaded counter. Slower evaporation usually yields larger crystals.
  • To grow a single large crystal, set a bit of solution on a shallow saucer and let it evaporate to form seed crystals. Select one or a few to place into your main solution to act as nucleation sites for crystal growth.​​​

Crystal Recipes

Here is a collection of crystal recipes:​

 Borax Crystal Snowflakes

These lovely snowflakes are easy to make and grow overnight. They make great holiday ornaments and can be kept for years.

Potassium Alum CrystalBig Alum Crystal

Alum crystals are easy to grow from a simple cooking ingredient. The large, clear crystals resemble raw diamonds.

Sugar Crystals

Sugar Crystals

Grow Rock Candy or Sugar Crystals

Most crystals you can grow look pretty, but aren’t good to eat. The biggest exception is rock candy, which consists of sugar or sucrose crystals. You can use any type of sugar you have handy, plus these are easy crystals to color and flavor.

Calcium Carbonate Crystals (Christophe Delaere)

Calcium Carbonate (Christophe Delaere)

Calcium Carbonate Crystals

All you need is a rock and some vinegar to grow either needle-like prisms or branched crystal ferns. The pure mineral is clear or white (aragonite), but you’ll get colored crystals if you grow the crystals onto a rock.

Salt Crystals (Choba Poncho)

Salt Crystals (Choba Poncho)

How to Grow Salt Crystals

While you could eat salt crystals, they aren’t likely as good as rock candy. That’s okay, because the cubic crystals are beautiful to look at! You can use any type of salt and may enjoy exploring the different appearances you’ll get, depending on what you use. Salt doesn’t pick up color the way sugar does, so expect these crystals to be clear or white.

Copper Sulfate

Copper Sulfate (Stephenb)

Blue Copper Sulfate Crystals

You don’t need dye to get the bright blue color of these crystals. Copper sulfate is easy to find, naturally blue, and grows stunning diamond-shaped jewel-like crystals. This is a good project to try if you want to grow a large single crystal.

Rochelle Salt CrystalsRochelle Salt Crystals

Rochelle salt crystals are large, clear crystals that generate electricity under pressure. They are easy to grow from baking soda and cream of tartar or from the pure chemical.

Bismuth crystals (Dschwen)

Bismuth crystals (Dschwen)

Bismuth Crystals

You don’t have to dissolve anything to grow metal crystals and you don’t have to wait for results. Melt the bismuth and see the rainbow!

Crystal TreeUrea Crystal Tree
These crystals grow in minutes, while you watch. They resemble a flower or a tree, depending on the shape you use.

Epsom salt crystals readily absorb food coloring.

Epsom salt crystals (Jason D)

Epsom Salt Crystals

Epsom salt is non-toxic and inexpensive. It produces beautiful crystals easily colored with food coloring.

Green Crystal NeedlesCup of Crystal Needles

Grow Epsom salt crystal needles in your refrigerator within a few minutes to couple of hours.

Hot ice is another name for sodium acetate.Hot Ice or Sodium Acetate Crystals

Make sodium acetate from baking soda and vinegar and use it to make hot ice.

Imitation Emerald CrystalImitation Emerald Crystals

These monoammonium phosphate crystals look like emeralds. Control the growing conditions and colors to make imitation amethyst, citrine, and aquamarine.

Crystal GardenGrow a Charcoal Crystal Garden

This is the classic crystal project where you would pour a mixture of salt, laundry bluing, and vinegar over a brick or charcoal briquette. However, you can take these crystals to the next level by making a scene out of cardboard. Use food coloring or a marker to tint the crystals.

Potassium nitrate crystals form needle shapes when crystallized from water.

Adam Rędzikowski

Make Potassium Nitrate Crystals

Get potassium nitrate or saltpeter online or as stump remover from a store. Like Epsom salt, this chemical forms sparkling crystal needles immediately upon cooling.

Chrome Alum

Chrome Alum (Ra’ike)

Purple Chrome Alum Crystals

Grow natural purple chrome alum crystals. This is a chemical you can make or find online that dissolves into a blue-green solution, but produces stunning purple octahedral crystals. If you mix regular alum with chrome alum, you can get crystals ranging from lavender to deep amethyst.

 These calcium chloride crystals grew spontaneously in a container of DampRid.Clear Calcium Chloride Crystals

Grow sparkling six-sided calcium chloride crystals from a chemical found in most homes.

Potassium Dichromate CrystalsOrange Potassium Dichromate Crystals

Grow bright orange potassium dichromate crystals. The color is natural and doesn’t require any dye.

Copper Acetate Crystals

Choba Poncho

Blue Green Copper Acetate Crystals

Grow naturally blue-green crystals from copper acetate. This is a chemical you can make by reacting vinegar and peroxide with pennies or copper wire or you can find the pure chemical online. These crystals exhibit an interesting shape and gorgeous color.

Color change crystalsEasy Color Change Crystals

Light and temperature shift the color of these crystals between yellow, green, and blue.

Storm Glass Barometer Crystals (Eigenes Foto)

Eigenes Foto

Make a Storm Glass Crystal Pendant

This is like a mood ring, except it grows different shapes of crystals rather than changing colors. Does it actually predict your mood? Probably not, but it’s still super cool!

How To Make Crystals Glow in the Dark

Learn how to make quartz and other translucent crystals glow in the dark. The technique relies on phosphorescence, so once the crystal is exposed to light, it stores the energy and releases it as different colored light. You can get a crystal to grow all night long.

Black Borax CrystalsHow to Grow Black Crystals
Can’t afford black diamonds? Grow solid black or translucent black crystals by either dying the crystal-growing liquid or using a black base beneath clear crystals.

Over time, monoclinic needle crystals spontaneously change shape into rhomboid sulfur crystals.

Mike Beauregard

Grow Sulfur Crystals
Learn two different methods to grow sulfur crystals. These crystals spontaneously change shape over time.

Crystal Flower

Crystal Flower

Grow Crystals To Preserve a Real Flower

Actually, you could preserve a plastic or silk flower too, but where this project really shines in in preservation of real flowers. It could be a flower from a special event or from your garden. Crystallizing it is a way to make it last forever.

Maple Syrup Crystals (Jody McIntyre)Maple Syrup Crystals

These edible crystals are a type of sugar crystal that grows from maple syrup. You can use the same technique to grow corn syrup crystals, too.

Salt Crystal Geode

Salt Crystal Geode

Grow Your Own Crystal Geode

Nature takes thousands of years to produce a geode, but you can make one overnight. Your geode will consist of real crystals on real minerals, plus you can customize the color.

Glowing Geode

Glowing Geode

Make a Glowing Crystal Geode

Add a simple ingredient to turn an ordinary crystal geode into one that glows in the dark or glows under black light.

 Borax Crystal Heart

Grow crystal hearts for Valentine’s Day decorations or to attach to gifts for friends and loved ones.

Crystal Egg

Crystal Egg

Make a Crystal Egg

Grow crystals on the surface of an egg for a decorative Easter project or simply as a beautiful ornament. You can hollow out the egg first or grow crystals on a raw or boiled egg. If you use table salt for the crystals, you can eat the crystal egg, too.

Grow Crystals on a Starfish

Crystallize a read starfish to use for a decoration or ornament. Don’t have a starfish? Try a shell or sand dollar. You can use any of a number of common household chemicals to get the effect.

Potassium ferricyanide crystals

Maxim Bilovitskiy

 Grow Natural Red Potassium Ferricyanide Crystals

These lovely crystals are a natural red color. The cyanide in the chemical is bound into the molecule, so it does not pose a threat, either making the crystals or disposing of leftover chemical solution.

Borax Crystal Star (Anne Helmenstine)
Borax Crystal Star

Bend a pipe cleaner into a star shape and coat it with crystals to make a sparkling ornament. Rather than color the crystals, use an iridescent or shimmering pipe cleaner to make the star glisten.

A seed crystal is a small crystal used to promote growth of a larger one.

photo: Ude

Grow a Seed Crystal

Grow a seed crystal to use as a base to make a perfect large single crystal.

Green Rock Candy

Green Rock Candy

My Crystals Won’t Grow! Here Is How To Fix It

If your crystals won’t grow, don’t give up or throw out the chemical solution. Sometimes all you need is a little more time or to change the temperature of the liquid. There are other tips that can save your crystals or help you improve your procedure if you decide to start over.

Copper Acetate Monohydrate CrystalsHow to Preserve Crystals

Do you want your crystals to last? Learn how to preserve them for display or use in jewelry.