Create real crystals at home that will literally grow right in front of your eyes with Schylling's Crystal Hedgehog. They fully grow in 24 hours! Crystal Hedgehog is a great STEM to learn basic science and chemistry while having fun. You will end up with a great souvenir when you’re done! Contains everything you need: crystal powder, gypsum base, growing container, stir stick, complete instructions and the Hedgehog. Non-toxic. Safe for boys or girls ages 8+.