Septarian nodules from UT are usually complete nodules, but a few have been sawed in half such as the image to the left, a 26 pound half, measuring about 11" x 12" x 4".(Stock 645) The septarians are getting harder to come by, and now most nodules in stock are above 15 pounds per nodule, if complete.  Some smaller sizes have been sawed in half, etc. The septarian nodules may be solid or have a geode center with possibly yellow calcite crystals lining the cavity, if in geode form. Some will have crystal lined geode small pockets as the image to the left.  Fossils have been found in some septarians. One fossil found in a septarian nodule, to the delight of it's owner, was right in the middle of the nodule when it was slabbed. It turned out to be a 3" ammonite. The brown lines in the septarians are aragonite and the outside matrix is limestone with yellow calcite centers. These will take a nice, interesting polish. Septarian nodules when prepared and polished will make beautiful spheres, specimens, bookends, clock faces and more. Check out some other web sites which offer septarian nodule spheres, priced at many hundreds of dollars. All septarians have some natural fractures and as a safety measure, it is adviseable to reinforce any noticeable fratures with Red Label Hot Stuff or Crazy Glue before sawing the septarian in half or slabbing. This will help guard against the possibility of breakage if they have a large void, which could be damaged, when the piece falls in the saw.