How to Make Rock Salt

Rock salt is a natural, unrefined salt consisting of large crystals with mineral impurities. Sometimes the impurities color the salt. For example, natural salt occurs in white, pink, red, and black. The grain size, color, and flavor make rock salt popular for recipes, bath products, and crafts, but it can be expensive! You can make your own rock salt substitute from regular table salt.

Rock Salt Materials

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How to Grow Table Salt or Sodium Chloride Crystals

By Anne Marie Helmenstine, Ph.D.

• Salt (NaCl) - You can use iodized salt, uniodized salt, or sea salt.
• Water
• Food coloring (optional)

Grow Rock Salt Crystals

1. Heat the water to a rolling boil. Very hot tap water is not hot enough because salt solubility depends on temperature.
2. Stir in salt until no more will dissolve.
3. If desired, add a couple of drops of food coloring. Two drops of red and one of yellow will give you rock salt that resembles pink Himalayan rock salt.
4. Pour the solution into a clean container. For the cleanest crystals, avoid getting undissolved salt into this new container. On the other hand, for the quickest results, leave the undissolved salt to help start crystal growth.
5. Let the salt crystals grow. As the water evaporates, the liquid becomes more concentrated and the crystals will grow more quickly.

• When you are satisfied with the amount you have (or the crystals stop growing), pour off the remaining liquid and let the salt dry. You can break it into pieces and store it in a sealed bag or jar.