How to make crystals from coal

Updated July 20, 2017

The process of growing crystal flowers using coal as a base originates in early American society. According to The American Coal Foundation, "the making of coal flowers is a historic craft that was practised by coal mining families in the late 1800s and early 1900s. When mining families had little money to buy decorations or purchase toys, they used common household products and coal to make beautiful crystal flowers." The coal provides a porous material from which the crystals grow. This project provides as interesting results today as it did 200 years ago.

Break up the charcoal briquettes into roughly 1-inch chunks. Use a hammer, but don't pulverise the charcoal.

Arrange the briquettes in the glass bowl in an even layer.

Combine the Bluing, water, salt and ammonia in the mixing bowl, and mix them well. Some salt will remain in the bottom of the bowl.

Pour the combined mix over the coal pieces, including the extra salt.

Add food colouring on top of the mixture as desired. Any spots that are not coloured will grow white crystals.

Sprinkle 2 tbsp extra salt over the entire charcoal crystal bed. Wait two days.

Combine 2 tbsp each of the Bluing, ammonia and water, and pour the mixture over the pan of charcoal. Do this again on day three.

The crystals begin growing within a few hours of the creation of the project and will fully form in two to three days up to a couple weeks.


Mrs. Stewart's Liquid Bluing can be hard to find in stores. Check chemists, and online outlets. Circulating air helps the crystal growing process. The drier the growing space, the better the crystals will grow. Keep your garden growing by continuing to add a mixture of ammonia, Bluing, salt and water. Position pipe cleaners in and around the coal, and the crystals will grow up the pipe cleaner, building tree-shaped formations. Add toothpicks, twigs, paper, cloth or string to the charcoal base to create different shapes for the crystals to grow onto. Any porous material can be used to grow the crystals. Try brick, cork or sponges, in addition to the coal or charcoal.


Bluing can be harmful to skin, eyes and if ingested; use with caution. Ammonia is irritating to the eyes, nose and throat. Persons with lung issues should also be wary of inhaling ammonia; it is classified as an inhaled irritant.

Things You'll Need

  • Hammer
  • Shallow glass bowl
  • Charcoal briquettes (or brick pieces or small porous stones)
  • Mixing Bowl
  • 6 parts Mrs. Stewart's Liquid Bluing
  • 6 parts water
  • 8 parts salt
  • 1 part ammonia
  • Food colouring (optional)
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About the Author

AnnaBeth Hawkins Davidson has been a freelance writer/editor since 1999. She has written pieces for and Davidson studied English Literature at Regis University in Denver, Colorado for several years, and received a Bachelor of Music in vocal performance at the University of Denver's Lamont School of Music.