Third Grade
Worksheets
Jewel Cave National Monument
The third-longest cave in the world is found in South Dakota. Its name is Jewel Cave. It is a national monument. The name comes from the crystals that line the inside of the cave. The crystals are made of calcite. Calcite is a white or colorless crystalline mineral.
Many caves are carved by underground rivers. That is not how Jewel Cave was formed. The cave was carved by acid-rich groundwater that moved slowly in circles. When Jewel Cave was first made a national monument, the size of the cave was unknown. People thought the crystal formations were pretty. They wanted to preserve them. In later years, the cave was explored more. It was even longer than was first thought. In 2017, Jewel Cave had 195 miles of mapped passageways, and experts believe there are still more parts of Jewel Cave to be discovered.
