Grow your own crystal creations! Non-toxic, child-safe kit grows an intensely-colored amethyst purple crystal up to 5" (diameter) in size. The secret is in the crystal seeds which are placed on the rock base. Small crystals will form within 6 hours and continue to grow for several days. Use a flashlight to check the progress of the daily growth. Fascinating to watch and stunning to display. includes step-by-step instructions. It's perfect for observation / science project.