48 tough crystal-like rocks in 8 shapes and 6 rich translucent colors. Use the picture cards to challenge your students. Stack, arrange, count and sort by color and shape. Perfect for light tables. Check out our instructional video. Includes 48 Stones, up to 2x2" (5x5 cm), 18 double-sided challenge cards, 4x6" (10x15 cm) and storage box.