Solutions to Common Crystal Growing Problems

Green Rock Candy

Green Rock Candy (Anne Helmenstine)

Sometimes crystals just don’t seem to grow no matter what you try or you get a mass of tiny crystals when you want a single large crystal. Here’s a look at some of the most common problems you may encounter when growing crystals. Find out what you can do to correct some problems without throwing out your solution or prevent the same problem if you have to try again.

Crystal Growing Problem #1: No Crystal Growth

This is usually caused by using a solution that isn’t saturated. The cure is to dissolve more solute into the liquid. You can stir the solution and apply heat to help to get solute into solution. You want to keep adding solute until you start to see some accumulate at the bottom of your container. Let the excess 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 to use, you can take some comfort in knowing that the solution will become more concentrated over time, as evaporation removes some of the solvent.

You can speed the evaporation process 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. Don’t seal the container. If you are sure your solution is saturated, try to eliminate these other common reasons for lack of crystal growth:

  • Too much vibration
    Grow your crystals in an undisturbed location.
  • Contaminant in the solution
    The fix is to re-make your solution. If your starting solute was impure, you will need to make the new solution with a higher-purity compound. Common contaminants that enter the solution after you have made it include oxides from paper clips or pipe cleaners, detergent residue on the container, dust, or a contaminant falling into an uncovered container.
  • Inappropriate temperature
    Experiment with temperature. You may need to increase the temperature around your crystals to get them to grow (increases evaporation). However, for some crystals, you may need to decrease the temperature (which slows the molecules down and gives them a change to bind together).
  • Solution cooled too quickly or 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 may make a difference. You can increase the rate of cooling by putting the fresh solution in a refrigerator or freezer (faster) or leaving it on a warm stove or in an insulated container (slower). If the temperature didn’t change, maybe it should during your next attempt (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
    This is not a likely problem with home crystals, but for certain materials the energy from light can inhibit the formation of chemical bonds.

Crystal Growing Problem #2: Seed Crystals Dissolve In New Container

This happens when the solution isn’t fully saturated. Try the tips just discussed to make a more saturated solution.

Crystal Growing Problem #3: No Seed Crystals

If you are trying to grow a large single crystal, you will need to get a seed crystal first. For some compounds, seed crystals may form spontaneously on the side of the container. For others, you may need to pour a small amount of solution into a shallow dish and let the liquid evaporate to get crystals. Sometimes crystals will grow best on a rough string suspended into the liquid. The composition of the string matters. You are more likely to get crystal growth on cotton or wool string than on a smooth nylon or fluoropolymer line.

Solutions to Common Crystal Growing Problems
Last modified: August 8th, 2015 by Anne Helmenstine

One thought on “Solutions to Common Crystal Growing Problems

  1. Pingback: Grow Table Salt or Sodium Chloride Crystals | Science Notes and Projects

Comments are closed.