Septarian Nodules – Orderville, UT

Orderville, Utah is famous for the thousands of Septarian Nodules which have been mined and sold to the public.  Our members have taken two trips there in the last 6 months and enjoyed it both times.


There’s much speculation about how they formed, but no certainty as to what they contain.  The word “Septarian” comes from the Latin word “septum which means partition.  The insides of the nodules are partitioned and often contain fossils, of which ammonites and snail are the most common.


Arriving at the beds you discover mounds of gray/brown dried mud, with layers of drusy so fine it crumbles in your hands.  There are a number of layers, but nothing consistent.  I found this little calcite crystal turned upside down on the dried mud.






The beds of nodules in Orderville are comprised of Limestone, which includes Barite, Siderite, and Calcite.  The Barite is a yellow-brown and has a hardness of 3.  Siderite is an ore of iron, is brown and has a hardness factor of 3 ½ – 4 ½ .  Calcite is colorless to yellow-gold, has a hardness of 3 and usually is inside the nodules in the form of crystals.    Limestone forms in warm, shallow seas and is normally found with shell and skeletons of marine organisms.  As you can tell from the hardness rating, these are soft stones.  Making Cabochons is tricky, but it makes wonderful carving material.

Utah Septarians range in size from an inch to three feet.  Most of those found in Orderville are an average of 3-5 inches.

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