Troubleshooting Problems in Crystal Growing

What to Do When Your Crystals Won't Grow

Sugar crystals or rock candy

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Growing crystals is fairly easy and a fun project but there may come a time when your attempts to grow a crystal won't be a success. Here are some common problems people run into and ways to correct them:

No Crystal Growth

This is usually caused by using a solution that isn't saturated. The cure for this is to dissolve more solute into the liquid. Stirring and applying heat can help to get solute into the solution. Keep adding solute until you start to see some accumulate at the bottom of your container. Let it settle out of solution, then pour or siphon the solution off, being careful not to pick up undissolved solute.

If you don't have any more solute, you can take comfort in knowing that the solution will actually become more concentrated over time as evaporation removes some of the solvents. You can speed this process up by increasing the temperature where your crystals are growing or by increasing air circulation. Remember, your solution should be loosely covered with a cloth or paper to prevent contamination, not sealed.

Saturation Problems

If you're sure your solution is saturated, try to eliminate these other common reasons for the lack of crystal growth:

  • Too much vibration: Keep your crystal setup in a quiet, undisturbed location.
  • Contaminant in the solution: The fix for this is to re-make your solution and only works if you can avoid contamination. (It won't work if your starting solute is the problem.) Common contaminants include oxides from paper clips or pipe cleaners (if you're using them), detergent residue in the container, dust, or something else falling into the container.
  • Inappropriate temperature: Experiment with temperature. You may need to increase the temperature around your crystals to get them to grow (this increases evaporation). For some crystals, you may need to decrease the temperature, which slows the molecules down and gives them a chance to bind together.
  • Solution cooled too quickly or too slowly: Did you heat your solution to saturate it? Should you heat it? Should you cool it? Experiment with this variable. If the temperature changed from the time you made the solution to the present time, the rate of cooling might make a difference. You can increase the rate of cooling by putting the fresh solution in a refrigerator or freezer (faster) or leave it on a warm stove or in an insulated container (slower). If the temperature didn't change, perhaps it should (heat the initial solution).
  • Water wasn't pure: If you used tap water, try re-making the solution using distilled water. If you have access to a chemistry lab, try deionized water that was purified by distillation or reverse osmosis. Remember: water is only as clean as its container! The same rules apply to other solvents.
  • Too much light: The energy from light can inhibit the formation of chemical bonds for some materials, although it's an unlikely problem when growing crystals at home.
  • No seed crystals: If you're trying to grow one large single crystal, you'll need to start out with a seed crystal first. For some substances, seed crystals may form spontaneously on the side of the container. For others, you may need to pour a small amount onto a saucer and let it evaporate for crystals to form. Sometimes crystals grow best on a rough string suspended into the liquid. The composition of the string is important! You're more likely to get crystal growth on cotton or wool string than on nylon or a fluoropolymer.
  • Seed crystals dissolve when placed in the new container: This happens when the solution isn't fully saturated. (See above.)