Bedrock under this museum, 530 million years old. During the continental collisions that built the Appalachian Mountains, heat and pressure transformed a sedimentary rock into this folded metamorphic rock.
The red thumbprints in this rock are garnets that grew when the rock was glowing hot, 16 km (10 mi) below Earth's surface. The garnets took about 12 million years to get this big. In the process they rolled slowly like snowballs! The peculiar S-shaped patterns within the garnets are made of minerals trapped as the garnets grew. 400 million years old