The oldest rocks in Kansas are found in Blue Rapids as Sioux Quartzite, a metamorphosed red sandstone originally deposited as sand in riverbeds, then buried and made extremely hard by heat and pressure. This quartzite formed over 1.5 billion years ago in what is now southern Minnesota, and in Kansas only meteorites are older. Glaciers picked up pieces of Sioux Quartzite near Pipestone, Minnesota, and carried them nearly 300 miles to northeastern Kansas. Blue Rapids residents used Sioux Quartzite boulders for building materials and decorative hardscaping. Pipestone was once river mud and part of the same river system that contained the sand that became Sioux Quartzite; it is now the special claystone from which Native Americans carved pipe bowls.