Crystal chemistry has never been so fast (grows in 3 - 4 days), fun, and colorful, making this the perfect educational activity or gift! FAST-GROWING CRYSTALS IN 6 COLORS - Grow blue, red, purple, green, yellow, and glow in the dark crystals! GROWING IS EASY – Easy-to-follow instructions and the 2 included silicone growing chambers make growing your crystals easier than ever!