Tag Archives: crystal growing

Crystal Rose – How To Crystallize a Real Rose

Crystal Rose

Crystal Rose (Anne Helmenstine)

Grow crystals on a real fresh or dried rose. The crystal rose is preserved, so it will stay sparkling and beautiful.

Crystal Rose Materials

You’ll probably get the prettiest crystal rose using a bud, but I had an old rose in my garden, so that is what I used.

  • rose
  • borax
  • water

Crystallize the Rose

  • Choose a cup or glass large enough to hold your rose.
  • Fill the cup with very hot water.
  • Stir in borax until no more will dissolve.
  • For large crystals that sort of resemble dew drops, invert the rose into the solution and allow it to crystallize for a few hours.
  • For small glittery crystals, filter the liquid through a paper towel or coffee filter to remove any undissolved borax. Pour the liquid into a clean, dry cup, add the rose, and allow it to crystallize for at least an hour. You can check on it periodically and remove it when you get the look you want.
  • Remove the crystal rose and place it on a paper towel to dry. Once dry, you can place the rose in a vase, if you like.


The solubility of borax depends on temperature. If you want to get a highly saturated solution, use boiling water. Let it cool down near room temperature before adding the rose or else you’ll basically cook it. This leaches the color from the petals and gives you a droopy-looking flower.

The borax may alter the color of the rose. The color change is partly because the pigments in the rose are affected by the pH of the liquid and partly because the salt may leach some of the pigment from the petals.

If you don’t have borax, you can use table salt, Epsom salt, or sugar. If your rose is free of pesticides and herbicides, a sugared rose will be edible.

If you don’t have a real rose, don’t despair. You can crystallize a pipecleaner rose just as easily… see how it works.


How To Make Rock Candy or Sugar Crystals

Rock Candy or Sugar Crystals

Sugar crystals are one of the few types of crystals you can grow that you can eat. (Anne Helmenstine)

Sugar crystals are called rock candy because these hard crystals are edible. Sugar (sucrose) crystals are one of the few types of crystals you can grow and eat. You can eat the natural clear crystals or you can color and flavor them.

Rock Candy Materials

  • 3 cups sugar (sucrose)
  • 1 cup boiling water
  • food coloring (optional)
  • flavoring (optional — good choices include cherry, peppermint, and cinnamon)
  • clean glass or plastic jar
  • wooden skewer or cotton string

Grow Sugar Crystals

The procedure is really easy.

  1. Dissolve the sugar in the boiling water. You can heat the sugar solution on the stove or in the microwave if you have trouble getting the sugar to dissolve.
  2. Add a few drops of food coloring and flavor, if desired.
  3. Allow the solution to cool a bit before pouring it into your jar. You don’t want to get burned!
  4. Pour the sugar solution into a jar. Place a wooden skewer into the jar or else hang a string into the middle of the jar, tied to a pencil or butter knife.
  5. Place the container somewhere it won’t be disturbed. You may wish to cover the jar with a paper towel or coffee filter to allow evaporation while keeping the crystal solution clean.
  6. It may take a few days to get good crystal growth. If you see crystals forming on the top of the jar, you can remove them and eat them. If you leave them, these crystals will compete with your stick or string for sugar and will reduce the size of your crystals.
  7. Remove the crystals and enjoy them! If you want to store the crystals before eating them, keep them in an airtight container so humidity in the air won’t make the rock candy sticky.

New Method of Creating Porous Silicon Crystals

Schematic of porous silicon crystal.  Credit: Donghai Wang, Penn State University

Schematic of porous silicon crystal.
Credit: Donghai Wang, Penn State University

Porous silicon crystals are simply silicon crystals with gaps in the structure on the order of 2-50 nanometers. These holes give the crystal a very large surface area to volume ratio. Porous silicon is used in a variety of applications, such as optical sensors, rechargeable batteries and tissue engineering. Porous silicon in solar panels can be used to split water into hydrogen and oxygen using sunlight.

Typically, porous silicon is produced by etching silicon wafers with strong acids and water or applying a current while the silicon is floating in a bath of hydrofluoric acid. These processes waste a lot of silicon to produce porous silicon. Mechanical engineers at Penn State have discovered a process to reduce that waste and create crystals with holes ranging from 5 to 15 nanometers in diameter. Their method builds the crystals rather than destroying silicon.

They start with silicon tetrachloride and begin breaking down the silicon-chlorine bonds with a sodium potassium alloy. The chlorine begins to form new bonds as the material dries with the sodium and potassium ions making sodium chloride and potassium chloride salt crystals embedded in the silicon crystal matrix. The material is heated to set the silicon matrix and then washed with water to dissolve and wash away the salts. The spots where the salt crystals were are now the holes in porous silicon.

Hopefully this new manufacturing process will make porous silicon more readily available to researchers and engineers to find new uses for this amazing material.

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.