When I was a boy I discovered the magic of growing crystals from various ingredients. That was shortly after I was so disappointed when my Sea Monkeys didn't look at all like monkeys. They didn't even have crowns or scepters. And my X-Ray Specs didn't work like they were supposed to, either. So I started growing crystals in my little bedroom laboratory.
I used salt, sugar, and alum. Each of these composites produce crystals with different structures. The salt crystals were always cubic. The sugar (which you could eat after they formed) were hexagonal with pointed ends. My favorite was the crystals produced with alum. In case you have a youngster, or a grandchild, this might offer you an opportunity for some quality time and a learning experience that could spark an interest in chemistry or science.
Just so you know, alum crystalizes in a tetrahedral form. The crystals form like two pyramids joined at the base.The photo above is of a chrome alum crystal. I'm sure what chrome alum is, but the crystals you can grow from regular alum look just like this except they are clear instead of black.
Below is a step-by-step procedure for turning common, white alum into beautiful, clear crystals that look like sparkling diamonds. What you need to do is to create what is known as a super-saturated solution. More material (salt, sugar, alum) will dissolve in hot water than will dissolve in cold. The higher the temperature, the more will dissolve and the more saturated the solution becomes. So here we go . . .
Step 1: If you don't already have some, go to the grocery store and buy a box of alum. You'll find it in the baking section or with the spices.
Step 2: Place a sauce pan containing one quart of water on the stove and turn it on.
Step 3: As the water starts to heat, begin pouring the alum into it, stirring with a spoon as you add it. Not too much at a time. Make sure it's all dissolved before you add more. Continue adding more alum until no more will dissolve. Try to keep the water temperature just a little below a rolling boil.
Step 4: After the water has cooled a bit, pour it into a a quart jar and leave it alone for a few hours.
If you've created a super-saturated solution, the alum will begin to form crystal within 24 hours. You will see them forming on the bottom of the jar. There will probably be several of them, so we want to remove a lot of them to give the others more room to grow. Otherwise you will end up with a "matt" of crystals on the bottom of the jar. And that's not what you want. We're trying to create three or four really nice crystals.
Step 5: In a day or two your crystals will have grown to 1/8 inch or so across. Get a long pair of tweezers and remove all of the small crystals. If you don't have a long pair of tweezers you can pour the solution carefully from your incubator jar into another container and then remove the crystals with a spoon. Examine them and pick a half dozen or so of the biggest or best ones and set them aside. Then pour the solution back into the jar and add your selected crystals. Try to arrange them so they're not touching each other.
Step 6: You'll need to turn your crystals every day so that the alum is added to each side equally.
IMPORTANT NOTE: Do not place a lid on the jar. If you do, the water can't evaporate. Evaporation is important so that the solution remains at a constant state of saturation and your crystal continues to grow. If you notice your crystals look smaller than they did the previous day that means the saturation level has decreased and the water is dissolving the alum from your crystals. If this happens, remove your crystals and create a new solution as explained in Step 2. But don't place your crystal back into this new solution until it has cooled to room temperature. Otherwise it will dissolve. Keep making new solutions as your crystal continues to grow until you get it to the size you want. Then you can take it out of the jar and put it on display. The air won't hurt it. Just don't let it get wet because they do melt in water.
Having written this, it makes me want to do it again. I'm going to go buy some alum. Have fun! If you have any questions, leave a comment and I'll try to answer it.