National Geographic Collection Crystal Grow is great fun for the whole family! Become a scientist and grow incredible purple crystals with this unique scientist collection! Learn interactively! After all, there is no better way to explore the world of science than to experiment yourself. Take a look at the exciting and colorful world of chemistry and geology! Not only will you find all the tools you need to grow your own crystal. National Geographic also includes a booklet with information on how the experiment works. You will also find real amethyst in the set so that you can compare it to the crystal you have grown. Age: 8+ years.