How to Grow Black Crystals 2

Black Borax Crystals

One way to grow black crystals is to grow clear crystals over a black surface.

Black crystals can look translucent, like black diamonds or smoky quartz, or opaque, like anthracite. You can take most crystal recipes and use them to grow black crystals.

The Secret to Black Crystals

While it’s easy to grow crystals in rainbow colors, black is a little trickier because a lot of black dyes are really dark versions of other colors. Your best bet is to use liquid black food coloring because it’s meant to appear black even when it’s diluted. If you use a lot of colorant, you can get opaque crystals. A smaller amount gives you see-through true black (not gray).

In addition to using the right dye, another tip is to use a black pipe cleaner as a base, either hanging into the crystal solution or else coiled up to form a fuzzy “rock.” While not essential, this gives more depth to the black color. You can even make clear crystals (no dye) appear black by growing them over a black base. For added interest, you could wrap the black pipe cleaner with a metallic silver, black, or colored stick to produce crystals that flash in the light.

Black Crystal Recipe

It takes a lot of black dye to make solid black crystals.

It takes a lot of black dye to make solid black crystals.

You can use most simple crystal recipes, as long as they normally produce clear crystals. Good examples of materials include sugar, borax, or Epsom salts. Don’t use a chemical that produces a cloudy effect (e.g., salt or calcium carbonate) unless you want gray instead of black.

  • Borax
  • Hot water
  • Black food coloring
  • Black pipe cleaners
  • Container

Before you start, test your food coloring to make sure it’s actually black. Add a drop to a cup of water and see what color you get. If it looks black, great! If not, try another brand.

  1. First, prepare the pipe cleaner so it will fit in the container. It doesn’t matter what shape you make, but you don’t want it to touch the sides of the container or else it will be hard to remove the crystals. For easy removal, you can wrap the pipe cleaner around a butter knife and let it hang into the jar so that it’s not touching the sides or bottom. Once you’re satisfied with the base, remove it and set it aside.
  2. Next, prepare the crystal solution. Fill the jar with very hot water. Stir in borax until it stops dissolving. You can dissolve about 3 tablespoons of borax for 1 cup of water. It’s not a big deal if there is a little undissolved borax left.
  3. Add black food coloring. Using a few drops will produce translucent black crystals. If you add a lot of dye, you can grow solid black crystals.
  4. Put the pipe cleaner in the container. Because the liquid is so dark, you won’t be able to watch the crystals grow. Resist the urge to keep checking them because this can stunt their growth. Wait several hour or overnight before removing the crystals.
  5. When the crystals have grown, set them onto a paper towel to dry. Be careful not to stain your hands or clothes. If you do get a stain, bleach removes food coloring (even black).
  6. Once the crystals are completely dry, you can seal them to preserve them. You can spray them with a sealant or paint them with a clear acrylic coat or clear nail polish.

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2 thoughts on “How to Grow Black Crystals

  • Greg Owen

    What brand black food coloring does not dilute to other colors? I tried McCormick’s black food coloring and it dilutes to a dark green color, no bueno for black crystals.

    • Anne Helmenstine Post author

      I used a food coloring gel. I don’t remember the brand, but I Googled “really black food coloring” and someone recommended Americolor super black gel. If McCormick is going green, you could try to counteract it with a bit of red.