Kat and I have been spending quite a lot of time outside lately, examining and collecting rocks. We’re captivated by the glittering greens, deep reds, and dramatic blacks that we see all around us. The type of rock that has most captivated Kat however, is the sparkling white of the Quartz Crystal. When she was 4 years old, she would go on collecting expeditions with her friends, amassing large piles of the white rocks. As she’s grown older, she’s used them to create land art, or line her garden. It came as no surprise to me that when we were contemplating our next week of geology study, that Kat suggested we study crystals.
Most minerals occur naturally, in their purest forms, as crystals. They can form in a variety of ways. Sometimes crystals are formed deep within the Earth, where intensely high pressures can cause the atoms of the minerals to align in a close, symmetrical pattern. A common example of crystals forming in this way is the diamond, formed when carbon sources are pushed together under such high pressures that they break down, pushing the atoms as close together as possible. Other crystals are formed when magma cools slowly, allowing the atoms of the elements within the magma to cluster together, growing symmetrically. In this instance, the shape of the crystal is dependant not only on the way the atoms lock together, but also on the room they have in which to grow. Some crystals can get very large if there is enough space.
Still, other crystals are formed when a mineral rich liquid solution begins to evaporate, or can no longer support the mineral in a dissolved liquid state. In this process, nucleation is what allows the crystals to grow. Minerals will sometimes dissolve when immersed in a liquid state. When they do, the atoms from those minerals will lock on to the water (or other liquid) molecules and lose their solid structure. As the water evaporates, the atoms of the minerals will slowly come together. Once there is a large enough number of them, they will begin to attract more atoms of that mineral at a faster rate. These atoms will link together in regular patterns, forming crystals. This process is called Nucleation and there are some really cool activities that you can do at home in order to observe this process in action…
A CRYSTAL FOREST
3 Tbs household Ammonia (NH3)
1 Tbs table salt (NaCl – Sodium Chloride)
3 Tbs laundry bluing
Cleaned toilet paper tube
Well ventilated area
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Put on your safety goggles!
Clean your toilet paper tube of any remaining bits of paper. Cut or tear the top half into strips, approximately 1″ in length.
Using your tablespoon, measure and pour the ammonia and bluing on to the paper plate. Make sure you are in a well-ventilated area or next to an open window! Ammonia is incredibly potent with its burning odor. Then, add the salt and gently stir the solution.
Place your toilet paper tube in the center of your plate and wait.
Check your toilet paper after 30 minutes, and note any changes that have occurred. Periodically check your toilet paper roll for new crystal growth. After 24 hours, it should be covered with crystals!
The salt crystals dissolve in the solution. As the liquid evaporates, the atoms begin to regroup together to reform into salt crystals. However, the addition of the bluing and ammonia also adds salt crystals! The ammonia reacts with the bluing and breaks down the iron and sodium, so that the sodium can be added to the table salt for faster nucleation! Here is a neat time lapse video of the crystals forming on the toilet paper roll. You’ll be able to see that there is one starting point where the atoms begin to group together, resulting in crystal growth. Once that nucleation occurs, other crystals quickly begin to add on as they become attracted to the initial site of nucleation.
There is another demonstration you can do to see this process in action, although this one runs the course of several days instead of 24 hours. The nice thing about this demonstration is that you can use different materials to see which will generate better crystal growth. We used four different surfaces and were pretty surprised with the results…
SALT CRYSTAL GARDEN
1 Tbs household Ammonia (NH3)
1 Tbs laundry bluing (this will stain your tablespoon)
1 Tbs table salt (NaCl – Sodium Chloride)
1 Tbs Distilled Water
A plastic container or shallow aluminum pan to hold your garden
A surface for the crystals to grow on (we used charcoal, sponge, clay brick and cement brick)
Hammer (if using a brick or charcoal)
A dry, covered area outside for the storing of your crystal garden
Food coloring (optional)
Put on your safety goggles! Then, clean your pan of any crust, stickers (if new), or plastic.
If you’re using bricks or charcoal for your garden, you’ll want to take them outside and break them into smaller (about 1″) pieces. You’ll definitely want your goggles on for this as tiny sharp rocks will be flying from your bricks. I hammered chunks off the brick and let Kat hammer a chunk off the charcoal. We also used pieces of sponge that we cut into small rectangles.
Take your supplies outside and get to work! Start by pouring 1 Tbs of Ammonia, 1 Tbs Bluing, 1 Tbs Distilled Water, and 1 Tbs of Salt into the pie pan.
Now you can begin placing your surface pieces in the pie pan. You’ll want to place them so that they are at least 0.5″ apart.
If you would like to add a splash of color to your garden, now is the time to add the food coloring! Place one drop of color onto each surface.
Wait. Within a half hour, we began seeing results. Within 24 hours, the results were stunning!
Make sure you “feed” your crystal garden daily. Add the same amount of ingredients as you did when you started the project, and keep going until you either run out of bluing or are done being entertained with your crystal garden. We found that at first, the materials we used differed greatly in crystal growth. The cement brick yielded the best results, followed closely by the clay brick. After a few days however, everything had pretty much evened out.
As we were monitoring our crystal gardens, we couldn’t help but marvel over the delicate crystal formations that were growing on the surfaces. When our paper towel roll “bloomed” it looked like a beautiful forest of soft crystal trees. As our outdoor garden grew, it quickly began to resemble the beautiful corals of the Great Barrier Reef. It was so wonderful to see the beauty that could result from such atomic arrangements. I wondered if we might be able to watch the progress under the microscope. I had never tried a crystal garden on a slide before, I wasn’t sure if it could be done, or if we could even view the crystals as they grew…
A GARDEN THROUGH THE MICROSCOPE
Glass medicine dropper
Household Ammonia (NH3)
Table salt (NaCl – Sodium Chloride)
A surface for your crystals will grow (we used brick, charcoal, toilet paper, and a sponge)
1. Put on your latex gloves and safety goggles!
2. This is going to closely resemble the larger crystal garden. You’ll want to break off tiny pieces of surface material. We chipped off a small piece of brick and charcoal, and ripped off tiny pieces of the toilet paper roll and sponge.
3. Take your eye dropper and drop one drop of each liquid onto the slide. As in the above experiment, everything is at a 1:1 ratio.
4. Add your surface materials to the slide.
5. Sprinkle 1 drop’s worth of salt over the liquid and surface materials.
6. Wait. Check the slide under the microscope periodically (every 5 minutes or so), monitoring for crystal growth. Within minutes, we were able to see some beautiful structures develop.
In the above photo, you can see some of the nucleation taking place. Crystal spikes are starting to reach out and form pretty patterns. My favorite thing about this photo though, is that you can also see the salts that have been broken down by the chemical reaction between the bluing and the ammonia. These tiny salt crystals were everywhere!
We checked under the microscope every few minutes. Because there was so little liquid to begin with, evaporation and nucleation occurred at a rapid pace. Within twenty minutes a full crystal garden had developed and we were able to see some stunning pictures at the microscopic level! Here are some of the larger crystals (these are the white crystals you see billowing out on the slide):
My favorite picture of all though, came from the garden after it had set. We could see the crystal garden in its larger form above, but we could also see some of the smaller crystals as they were beginning to form around it. Because we had such small amounts of liquid and the evaporation occurred so quickly, these crystals were sort of frozen in formation and they were stunning!
Looking at the crystals in this way was incredible. Not only could we see the stunning crystal forests grow in their larger forms, but it was thrilling to also be able to see them up close and in such detail under the microscope! Kat and I were both squealing in delight as we looked under the microscope and saw each new sparkly pattern emerge!
As we learned more about how crystals form and where they can occur in nature, it has made us really appreciate them when we see them. Sometimes, when we see crystals on the ground, we’re looking at time, heat, and pressure, and these effects on the structure of atoms. When we season with salt, or sweeten with sugar, we’re ingesting the results of mineral soaked solutions evaporating over time. Getting a really good look at the results of these processes has allowed us to really appreciate things in a fuller way. There is beauty all around you, you just have to look for it!
It may just be in your kitchen cabinets, as gems waiting to be discovered.