The “jewels” this cave was named for are Dogtooth Spar. These are calcite crystals with six sides and a sharp point like a dog’s tooth. There are also lots of what are called drapery formations (though I think they look more like jellyfish). It also has some of the boxwork formations, but there are far more of these in Wind Cave. You must be on a guided tour to go into the cave and we took their 1 hour, 20 minute Scenic Tour.