Copper sulfate crystals are very popular and are extensively used in laboratories. The distinctive characteristic of this crystal is the repetitive internal pattern, which gives them a unique shape. The crystals of copper sulfate, just like sugar crystals or alum crystals, have a specific internal structure due to a particular alignment of atoms and molecules.
Copper sulfate is a chemical compound that is prepared by reacting various compounds of copper with sulfuric acid (H2SO4). The chemical formula for copper sulfate is CuSO4, and it exists in various forms of hydration. For instance, CuSO4.5H2O is the pentahydrate form. The anhydrous form of CuSO4, without any water of crystallization, is white in color; whereas the salt CuSO4.5H2O, with 5 water molecules attached to it, is bright blue in color. This is the basic test between anhydrous and hydrous forms of copper sulfate salt. The colorless, anhydrous form of CuSO4 is used to prepare copper sulfate crystals by dissolving it in water.
Copper sulfate is used in destroying algae in water supplies, and are an important ingredient of Bordeaux mixture sprays (as a fungicide) to keep a check on plant diseases. They are also used in copper plating, anemia blood tests, and also act as a good desiccant (in anhydrous form).
How To Make Them
To make any kind of crystals, you simply need to dissolve the chemical a bit beyond saturation in water, then evaporate cool the solution. Generally, putting seed crystals or hanging a string or candy stick in the solution provides a surface for the new crystals to form. It is necessary to keep the solution undisturbed for growing the crystals.
Prepare a Saturated Solution of Copper Sulfate
Stir copper sulfate into a over-saturated solution in hot water (keep adding copper sulfate until no more of it can be dissolved). Just pouring this solution in a jar and waiting for a few days can give you the desired crystals, however, they may not be properly shaped. To grow perfectly shaped crystals, you can first grow seed crystals.
Growing a Seed Crystal
To grow proper crystals, first you can grow a small seed crystal that will help form a larger one in proper shape. Take a shallow dish or saucer, and pour a little of the saturated solution in it. Let the seed crystal sit in an undisturbed position for at least a day, and then slowly scrape it off the container, once it dries. Tie this seed crystal to a length of nylon fishing line.
Suspend the seed crystal into a clean jar that is already filled with the saturated solution described at the start of this task. Carefully place the seed crystal in the center and ensure it doesn't touch the sides of the jar. Also, don't let any undissolved crystals spill into the jar.
Try to keep the jar in a place where it can be left untouched for few days. Putting a paper towel or coffee filter on the container allows for proper ventilation for the solution to evaporate, leaving behind the copper sulfate crystals.
You can frequently take a look and see if the crystals are growing. If you find that some crystals are also growing sideways, carefully take out the seed crystal, and pour the solution into another clean jar. After a few days, you will be able to see blue crystals in your jar. You can keep it to dry, and after some time, your crystal will be ready for use. While making these at home, you have to be vigilant to not disturb the solution till the crystals have formed completely. If you take proper care and follow these steps carefully, then you can definitely make well-shaped crystals at home.