I was browsing YouTube, in search of some chemistry I could do at home. Google had failed to provide me with anything more complex than making ice cream, which does not count as chemistry in my book. And so for a couple hours I searched for anything that could sate my hunger for chemistry (while not being completely out of reach to a home chemist such as myself). And in my search I came across some videos about chemical crystal growing. Using easy-to-find chemicals and water, one could create all sorts of gorgeous crystals! Alas, I had found something intriguing. And so began my first foray into crystal growing.
Picking a Crystal to Grow
The first step was to decide which type of crystal I was going to grow. My main concerns were waiting time (how long it would take the crystal to grow) and the cost of the chemical. I chose Copper Sulfate (CuSO4) due to how cheap it is, and the fact that it grows relatively fast compared to some of the other choices. Copper Sulfate produces brilliant blue triclinic crystals. (Triclinic describes the shape of the crystal.) After some browsing on eBay I found Copper Sulfate in 113 gram bottles selling for $6. I would only need 100g, but this was the best deal I found. In the meantime of shipping I gathered up my other items I would need: Fishing line/filament line, cardboard, tape, and some kind of glass/plastic container.
Making the Copper Sulfate Solution
After the Copper Sulfate arrived, it was time to make the supersaturated solution. A supersaturated solution is a solution where the maximum solubility has been exceeded. Imagine dissolving salt in water, and continuing until the water cannot hold any more salt. This is a supersaturated solution. For chemical crystal growing, this is important because we need precipitate to form so that small crystals will start to grow. Precipitate is the formation or "falling out" of solids out of a supersaturated solution. So for my supersaturated solution I mixed all 113 grams of CuSO4 with 226ml of hot distilled water. (I had planned to only use 100 grams of CuSO4, but what am I going to do with 13 grams of Copper Sulfate? So I used 13% more water to balance everything out.) After mixing everything thoroughly in a plastic container I let the solution rest in a safe place for a day.
Picking a Seed Crystal
After a day had passed, it was time to pick a seed crystal. First, I filtered everything through a funnel with some paper towels. In the bottom of the container there was a layer of crystal that had formed. I broke it up with a spoon and put them on a paper towel. An ideal seed crystal would be free of impurities and have a very smooth surface. After choosing one I suspended it in the filtered solution by tying with it with the fishing line and wrapping it around some cardboard I cut out. Then, it was back into the cabinet to grow.
The Wait Begins
One thing about crystal growing is that while you are growing the crystals, there's not much to do other than stare at it. It was fun seeing how it was getting bigger, but for the other 23 hours and 59 minutes of the day there was nothing else to be done. Every week I filtered the solution again and removed any parasite crystals (other crystals stealing mass from the main one) I found. And after only 2 weeks (a very short time in comparison to some other crystals that take months to get to the same size) I felt it was big enough and removed it from the solution. I then painted the crystal with some nail polish to make it safe to touch (Copper Sulfate is a mild skin irritant). And then I was done! Most of the leftover CuSO4 I put back in the bottle. I'm keeping the leftover solution to grow some polycrystals (multiple crystals in one).
This is by far my favorite experiment I've done. Not many experiments create something that you can keep. I would recommend this for anyone careful enough, as most chemicals used in crystal growing are skin irritants and toxic. Copper Sulfate is commonly used as a root killer, so that should explain what it will do to your body if you ingest any. Although I didn't have all the proper equipment and such with this experiment, I still took measures to make sure no one got hurt. This was tons of fun, and I think I have found a new hobby. Next up for me are Potassium Ferricyanide crystals!
© 2021 Roman Luckett