Sometimes crystals just don’t 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 crystal growing problems and how to fix or prevent them.
About Growing Crystals
Growing crystals is a fascinating and rewarding activity that blends science and art. Crystals are admired for their beauty and used in various applications, from jewelry and decoration to scientific studies and technological advancements. The process also demonstrates fundamental scientific principles, making it a popular project for students, hobbyists, and researchers alike.
At its core, crystal growth involves the organization of molecules or atoms into a structured lattice. This process, known as nucleation, depends on factors such as solution concentration, temperature, and impurities. Understanding these principles helps troubleshoot common problems encountered during crystal growing.
Summary of Common Crystal Growing Problems and Solutions
Here’s a summary of common problems and solutions:
| Problem | Cause | Solution |
|---|---|---|
| No Crystal Growth | Unsaturated solution | Dissolve more solute until saturation is achieved. |
| Contamination | Use purified solute and distilled water. | |
| Incorrect temperature | Adjust temperature to encourage growth. | |
| Seed Crystals Dissolve | Solution not fully saturated | Add more solute or allow evaporation to concentrate the solution. |
| No Seed Crystals | Lack of nucleation sites | Use a rough string or evaporate a small sample to form seed crystals. |
Crystal Growing Problem #1: No Crystal Growth
This issue often stems from using a solution that isn’t saturated. Here are steps to diagnose and fix the problem:
Causes and Fixes:
- Solution Not Saturated:
- Fix: Dissolve more solute into the liquid. Stir the solution and apply heat to help the solute dissolve. Continue adding solute until some accumulates at the bottom of the container, indicating saturation. Let the excess settle out, then carefully pour or siphon off the solution.
- Evaporation Too Slow:
- Fix: Increase the temperature around your crystal setup or improve air circulation. Loosely cover the solution with cloth or paper to prevent contamination while allowing evaporation. Avoid sealing the container.
- Environmental Vibrations:
- Fix: Place your setup in an undisturbed location, away from vibrations caused by foot traffic or machinery.
- Contaminants in Solution:
- Fix: Remake the solution with purified solute and distilled or deionized water. Common contaminants include dust, detergent residues, or oxides from metals like paper clips or pipe cleaners.
- Temperature Issues:
- Fix: Experiment with temperature. Some crystals require higher temperatures to grow due to increased evaporation, while others need cooler environments to allow molecules to bind together.
- Cooling Rate:
- Fix: Adjust how quickly the solution cools. Rapid cooling (e.g., refrigeration) sometimes helps stimulate crystal formation, while slow cooling (e.g., using an insulated container) promotes large crystal formation. Try both approaches if unsure.
- Water Quality:
- Fix: Use distilled or deionized water to eliminate impurities. Ensure the container is also clean.
- Excess Light:
- Fix: Although rare, light energy inhibits crystal growth for some compounds. Move the setup to a darker location if necessary.
Preventative Advice:
- Always test for saturation before starting.
- Use clean, uncontaminated containers and tools.
- Minimize environmental disturbances like vibrations or sudden temperature changes.
- Record variables to refine your process over time.
Crystal Growing Problem #2: No Seed Crystals
For growing a large, single crystal, obtaining a seed crystal is essential. But, how do you get this crystal? Here’s what you do:
Fixes:
- Spontaneous Formation:
- Sometimes seed crystals form on the side of the container. Observe your solution closely.
- Evaporation Method:
- Pour a small amount of solution into a shallow dish and allow the liquid to evaporate. Small crystals form as the solvent evaporates.
- String Method:
- Suspend a rough string (cotton or wool work best) into the solution. Avoid smooth synthetic strings like nylon, as they discourage crystal growth.
If no crystal grow, likely the solution is not saturated. Add more solute, increase the rate of evaporation, or lower the temperature to decrease solubility.
Crystal Growing Problem #3: Seed Crystals Dissolve in New Container
Often, you stimulate crystal growth in a saturated solution by introducing a seed crystal. This crystal helps the solute deposit exactly where you want it and in a desired shape. If your seed crystals dissolve after being transferred to a new solution, it’s likely because the solution isn’t fully saturated.
Fixes:
- Dissolve more solute in the liquid before adding the seed crystal.
- Let some liquid evaporate from the solution to increase saturation.
- Chill the solution before adding the seed crystal.
General Tips for Successful Crystal Growth
- Patience: Crystal growth takes time. Avoid rushing the process.
- Record-Keeping: Track variables like temperature, humidity, and solution concentration to refine your method over time.
- Safety Precautions: Handle chemicals carefully and ensure good ventilation when using heat.
- Preventing Contamination: Always use clean containers and tools, and cover your solution to prevent dust and debris.
FAQs About Crystal Growing
Q: How long does it take to grow crystals?
A: The time varies depending on the compound and conditions but typically ranges from a few hours to several weeks.
Q: Why are my crystals irregularly shaped?
A: Irregular shapes result from uneven saturation, rapid growth, or impurities in the solution.
Q: Can I use tap water instead of distilled water?
A: Tap water often contains impurities that can hinder crystal growth. Distilled or deionized water is best.
Q: What compounds are best for beginners?
A: Common compounds include salt (sodium chloride), alum, and sugar, as they are safe and easy to use.
Q: Can I eat the crystals I grow?
A: Only consume crystals if they are made from edible substances like sugar or salt and are grown in a clean environment.
Additional Notes
Popular Compounds for Crystal Growing:
- Salt (Sodium Chloride): Easy and accessible. Non-toxic.
- Alum: Produces clear, sharp crystals. Non-toxic.
- Copper Sulfate: Reliable. Yields vibrant blue crystals.
Fun Facts About Crystals:
- Crystals form naturally in geodes and snowflakes through similar processes.
- The world’s largest natural crystal is a gypsum crystal found in Mexico, measuring over 36 feet in length.
Safety Tips:
- Never taste or touch chemicals used for crystal growing.
- Wear gloves and goggles when handling potentially hazardous materials like copper sulfate or alum.
References
- Burton, W. K.; Cabrera, N. (1949). “Crystal growth and surface structure. Part I”. Discussions of the Faraday Society. 5: 33. doi:10.1039/DF9490500033
- Burton, W. K.; Cabrera, N. (1949). “Crystal growth and surface structure. Part II”. Discuss. Faraday Soc. 5: 40–48. doi:10.1039/DF9490500040
- Markov, Ivan (2016). Crystal Growth For Beginners: Fundamentals Of Nucleation, Crystal Growth And Epitaxy (3rd ed.). Singapore: World Scientific. doi:10.1142/10127. ISBN 978-981-3143-85-2.
- Pimpinelli, Alberto; Villain, Jacques (2010). Physics of Crystal Growth. Cambridge: Cambridge University Press. ISBN 9780511622526.