Amazing Science Kits: Super Growing Crystals. Watch these crystals grow from tiny gems to magnificent crystals just by placing them in water. Use them over and over again! This kit contains 3 super growing crystal packets in assorted colors, 1 test tube, and an instruction sheet. Recommended for ages 8 and up. WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years. This set contains chemicals that may be harmful if misused. Adult supervision required.