How to Grow Aragonite Crystals

It's easy to grow aragonite crystals! These sparkly crystals only require vinegar and a rock. Growing crystals is a fun way to learn about geology and chemistry.

Materials To Grow Aragonite Crystals

You only need two materials for this project:

• Dolomite rocks
• Household vinegar

Dolomite is a common mineral. It is the basis for dolomite clay, which should also work for crystals, but if you grow them on a rock you get a beautiful mineral specimen. If you use clay, you might want to include another rock or a sponge as a base or substrate to support crystal growth. You can find the rocks at a store or online or you can play rockhound and collect them yourself.

How To Grow the Crystals

This is one of the easiest crystal-growing projects. Basically, you just soak the rock in vinegar. However, here are a couple of tips for the best crystals:

1. If your rock is dirty, rinse it off and let it dry.
2. Place a rock in a small container. Ideally, it will be slightly bigger than the rock, so you don't have to use a lot of vinegar. It's okay if the rock sticks out of the top of the container.
3. Pour vinegar around the rock. Make sure you leave an exposed space at the top. The crystals will start to grow at the liquid line.
4. As the vinegar evaporates, aragonite crystals will start to grow. You'll start to see the first crystals in a day. Depending on temperature and humidity, you should start to see really good growth around 5 days. It may take up to 2 weeks for the vinegar to completely evaporate and produce crystals as big as possible.
5. You can remove the rock from the liquid whenever you are satisfied with the appearance of the aragonite crystals. Handle them carefully, as they will be brittle and fragile.

What Is Aragonite?

Dolomite is the source of the minerals used to grow the aragonite crystals. Dolomite is a sedimentary rock often found along the shores of ancient oceans. Aragonite is a form of calcium carbonate. Aragonite is found in hot mineral springs and in some caves. Another calcium carbonate mineral is calcite.

Aragonite sometimes crystallizes into calcite. Aragonite and calcite crystals are chemically identically, but aragonite forms orthorhombic crystals, while calcite displays trigonal crystals. Pearls and mother of pearl are other forms of calcium carbonate.