In a crystal, atoms and molecules are arranged in a consistent, repeating pattern. Examples of natural crystals include amethysts and diamonds. Crystals have 219 possible symmetries, called crystallographic space groups, and they are grouped into 7 crystal systems.
These include: Isometric, where crystals form cubes or rectangular boxes, halite, or salt, is an example, Tetragonal, Orthorhombic, Monoclinic, Triclinic, Trigonal and Hexagonal, where crystals form hexagons, ordinary ice is an example.
You can grow crystals at home using products you already have on your shelf, such as sugar, salt, alum, borax, and Epsom salt. Growing crystals is a great activity to do with children, and homemade crystals make great Christmas gifts, beautiful ornaments for a Christmas tree, and in one case, a delicious sugary treat.
1. Sugar crystals
- 1 cup of water
- 3 cups of sugar
- A glass jar or measuring cup
- A pencil or a butter knife
- Cotton or wool string or yarn
Use a saucepan to boil the water, then stir in the sugar one teaspoonful at a time. Continue adding sugar until it will no longer dissolve in the water, and it starts accumulating on the bottom of the pan. This means your sugar solution is saturated.
If you want colored crystals, add a few drops of food coloring which you can buy on Amazon where you can also find heat-safe measuring cups. Then, pour the solution into the glass jar while avoiding pouring any of the undissolved sugar.
Tie the string to the middle of the pencil or butter knife, rest the pencil or knife on the jar's rim, and allow the string to dangle in the water as close to the bottom as possible without touching either the bottom or the sides of the jar.
Cover the jar with a paper towel and place it somewhere where it won't be disturbed. Crystal growth should start within a day, and you can let the crystals grow until they are as large as you want or they have stopped growing. Pull up the string, allow the crystals to dry, and enjoy a sugary treat.
2. Alum crystals
Alum is a spice that is most often added to pickling liquid to keep pickles crisp. You can find alum in the spice section of your local supermarket and you can buy a fishing line on Amazon. To grow alum crystals at home, you'll need:
- 1/2 cup hot tap water
- 2-1/2 tablespoons alum
- A nylon fishing line
- A pencil or butter knife
- Two glass jars
You have to use a nylon line because alum crystals won't adhere to it. To make alum crystals, pour the hot tap water into one of the jars and add alum until it stops dissolving. Leave the jar undisturbed overnight.
The next day, pour the alum solution from the first jar into the second jar. You will see small alum "seed" crystals beginning to form. Tie the nylon fishing line around the largest or best-shaped crystal, and tie the other end around the middle of the pencil or butter knife. Allow the fishing line to dangle in the jar, making sure the seed crystal is completely covered by the solution.
Cover the jar with a paper towel, and allow it to remain undisturbed. If you're patient, you can get alum crystals of startling size.
3. Borax crystals
Borax is a powder typically added along with clothes washing detergents to make clothes whiter. You can find it at your local grocery store in the detergent aisle or else you can buy it on Amazon. You can also buy the pipe cleaners on Amazon.
To make borax crystals, you'll need:
- Boiling water
- Pipe cleaners
- A pencil or butter knife
- Glass jar
To grow borax crystals, twist several pipe cleaners into a compact shape, such as a spiral. Tie a thread to each pipe cleaner, then tie the other end of the threads to the middle of the pencil or butter knife.
Pour the boiling water into the jar then add 3 to 4 tablespoons of borax for every 1 cup of water. Keep stirring until the water becomes clear, and a small pile of borax appears at the bottom of the jar.
Balance the pencil or butter knife along the rim of the jar, and allow the pipe cleaners to dangle close to the bottom of the jar without touching either the bottom or sides of the jar.
Cover the jar with a paper towel and put it somewhere where it won't be disturbed. The next day, remove the pipe cleaners and let them dry on a paper towel. While the borax crystals are clear, they will appear colored due to the colors of the pipe cleaners shining through.
4. Salt crystals
If you look at common salt grains under a microscope, you'll see that each crystal is actually a tiny cube. To grow salt (or sodium chloride crystals) you'll need:
- Table salt (un-iodized works best)
- Boiling water (distilled water works best)
- Glass jar
- Pencil or butter knife
In a saucepan, stir salt into boiling water until no more will dissolve, and any excess appears at the bottom of the pan. Pour the solution into a glass jar, making sure no undissolved salt gets in.
Hang a string from a pencil or butter knife, and allow it to dangle in the solution without touching either the bottom or the sides of the jar. Cover the jar with a paper towel, and set it somewhere cool where it won't be disturbed. Within a day, you should see beautiful salt crystals forming.
5. Epsom salt crystals
You can buy Epsom salt at Amazon or at your local grocery or drug store. To grow Epsom salt crystals, all you'll need is a heat-safe cup such as a glass measuring cup.
Add 1/2 cup of Epsom salt to 1/2 cup of very hot tap water and stir for at least one minute. This creates a saturated solution where no more Epsom salt can dissolve. Add a couple of drops of food coloring if you want your crystals to be colored.
Place the measuring cup in the refrigerator to cool the solution quickly. In a few hours, you should see beautiful crystals. Pour off any remaining solution and allow the crystals to dry.
6. Copper sulfate crystals
You can buy copper sulfate powder on Amazon. To make copper sulfate crystals, you'll need:
- Copper sulfate
- Glass jar
- Small plate
- Butter knife
Avoid touching either the crystals or the solution because copper sulfate can stain both skin and fabrics. It's a good idea to use rubber gloves.
Stir the copper sulfate into boiling water until no more will dissolve. Pour a small amount of the solution onto a small plate, and reserve the rest. The larger surface area of the plate will help the copper sulfate solution to quickly evaporate, leaving behind small seed crystals.
Select the best seed crystals and use the butter knife to carefully scrape them off the plate. Pour the remaining solution into the jar, and place the seed crystals into the jar, making sure they aren't touching one another. Place the jar somewhere where it won't be disturbed.
Once you are satisfied with the size of the crystals, you can scrape them from the jar using the butter knife. You must store your finished copper sulfate crystals in an air-tight container, such as a plastic bag, because the water contained in the crystals will evaporate, and the crystal will turn a greenish-gray.
7. Sulfur crystals
You can purchase sulfur powder at Amazon. Making sulfur crystals uses a process different from what we have seen above, called a hot melt. Because sulfur can catch fire, it's a good idea for an adult to supervise making sulfur crystals. All you'll need is:
Melt the sulfur in the saucepan, being careful not to let it catch fire. Once it is completely melted, remove the pan from the heat and the sulfur will crystalize as it cools.
8. Bismuth crystals
You can buy bismuth blocks on Amazon. They are plain, gray blocks, but when melted then allowed to cool, Bismuth transforms into a beautiful stair-step crystal with iridescent colors. The colors are created by the interference of light within the oxide film that forms on the surface of the crystals as they cool.
What you'll need to make Bismuth crystals are:
- 2 stainless steel saucepans
- A fork
Once you use these saucepans to heat the bismuth, you should never use them again for food preparation because bismuth is a heavy metal and can be toxic. Also, it's a good idea to use rubber gloves to protect against splashes.
Place the bismuth in one of the saucepans, and heat it over high heat until the bismuth melts. A gray skin that contains impurities which will prevent crystals from forming will appear at the top. Use the fork to move the skin to the side of the pan while pouring the bismuth into the second preheated saucepan.
Cool the second saucepan slowly because the slower the cooling, the larger the crystals will be. When crystals start to form after about 30 seconds, pour any remaining liquid bismuth away from them. Once fully cooled, you can snap the crystals out of their metal container. Bismuth crystals can be made into beautiful jewelry.
9. Lead crystals
You've probably heard the term "lead crystal" which refers to glass that contains a large amount of lead. It is different from crystals that are formed from lead. Lead crystals are also called "The Tree of Saturn" because Saturn was the alchemical name for lead.
- Lead acetate solution
- Zinc strip
- A brass nut
To grow lead crystals dissolve 0.35 oz (10 grams) of lead acetate in 3.38 fl oz (100 ml) of water. Add to the solution a zinc strip and/or a brass nut because brass contains zinc. Black crystals will start to form in what's called a single displacement reaction during which the lead acetate reacts with the zinc to form zinc acetate and elemental lead crystals.
The crystals form in an upside-down tree structure, hence the name "Tree of Saturn." When taken out of the solution, the lead crystals quickly oxidize and a gray or white coating of lead oxide will form on their surface.
No matter what types of crystals you make, growing crystals at home will be something your kids will remember for a lifetime.
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