There are so many reasons why crystal growing kits help get kids interested in science. One is that it proves the existence of molecules—something that they can’t see, but that the formation of crystals need to exist. Another is that kids get to make the crystals themselves, which they can keep and show off. Plus, it’s just so cool! Anyone can see the crystals forming, and then actually hold a crystal in their hand and examine it.

The process of growing crystals is the same for most crystal growing kits—mix a solution, pour it into a container, add a “seed” onto which the crystals will begin adhering, and put the container in a place for several days where it won’t be disturbed. But the kits themselves, and what comes in them, vary. The one to get depends on what your child likes, and his or her maturity level. Here’s how to zero in on the right one.

This collection comes with seven sets, plus display cases to show off your hard work. 4M

The most rudimentary crystal growing kits contain only the materials needed to form crystals. If you’re not sure if your child will enjoy making crystals, these are your best bet because you won’t be making a big investment. Conversely, if your child thinks growing crystals is awesome, you can get two basic kits for the same cost as a kit with many extras.

Great Value

LED stands illuminate these colorful sets. Dan&Darci

Crystal growing kits provide the resources to grow translucent crystals in various colors. What’s more, you can transmit light through them, making them glow and shine—which looks awesome in a dark room. Kits that come with light-up stands let your child show off their good work, and the illuminated displays act as a cool nightlight—and a perfect one for the budding scientist.

Easy to Use

This kit lets kids compare what they just created with what’s found in nature. NATIONAL GEOGRAPHIC

It’s one thing for a kid to learn what a crystal is and grow one. It’s another to see and hold a crystal formed in the natural world and compare it to a crystal they just made in their kitchen. It creates a connection between the two and makes the science behind the crystal growing real—something that would intrigue many kids and inspire them to learn more about the earth.