My favorite of the many magnificent cave formations at Crystal Cave in Sequoia National Park (CA) was the Fairy Pools. Also located in the Dome Room, these delicate flowstone dam pools are perfectly framed by other cave formations which make them look like they do come out of some type of fairy tale:
The Fairy Pools are right along the cave path which allows you to inspect them closely (not from a distance as with many of the other popular formation within the cave). This allows you to see up close and personal how calcite makes many different types of cave formations in a single spot:
