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January 14, 2017

Septarian Nodule – Fossil or Gemstone?


Although Septarian Nodules might resemble some sort of ancient critter, it is a gemstone and not a fossil.  It is ancient in age due to the vast number of years it took the crystal to form inside the nodule.

What is a Fossil?

Fossils (from Classical Latin fossilis; literally, “obtained by digging”)[1] are the preserved remains or traces of animals, plants, and other organisms from the remote past.


What Is a Gemstone?

gemstone (also called a gemfine gemjewelprecious stone or semi-precious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments.[1][2] However, certain rocks (such as lapis lazuli) or organic materials that are not minerals (such as amberjet, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value.Gemstone Necklace


Why is it called a Nodule?

A nodule is a rounded mineral accretion that differs in composition from its surrounding rock.  Unlike a concretion that is formed from the materials where the rock is located like a Moqui Marble which has a sand core with and Iron Concretion outer layer.  They are found in sandy areas of Southwestern Utah.

A Septarian Nodule is not a nodule but a concretion.  They are found in ancient swamps of clay-like material and one theory as to their formation is the brine has percolated up through the cracks in the harder material.  These cracks are filled with calcite – thus the white veining. The first naming of Septarian called it a Nodule and has never been changed.

Why is It called Septarian?

The word “Septarian” comes from the Latin word “septum” which means “partition”, in reference to the fractured internal appearance.  These “veins” of color vary by location.  Utah Septarian from Orderville have a gray exterior and rich brown layer of siderite between the calcite layers.  Nodules from the Canyonlands area of Utah are more reddish on the outside and paler inside.

How do I take care of my gemstone jewelry?

With the utmost care.  The process of cabbing and polishing these ancient specimens requires patience and care.  The matrix is hard (Mohr’s 5-7 out of 10) but the veins are calcite which only has a hardness of 3.  As with all jewelry of natural materials, use plain water to bathe them as the chemicals in Windex and other cleaners will harm the stone.  You might consider taking them to a local Jewelry store for a professional cleaning that will take care of the mounting materials as well as the stone.

Have more questions about this or other gemstone and fossil jewelry?  Leave a comment and we’ll give you an answer.