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Septarian Nodule Slice by Undistilled Septarian Nodule Slice by Undistilled
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Title: Septarian Nodule Slice
Medium: Digital Photography
Photographer: Aaron J. Greenblatt
Camera Type: Panasonic DMC-LZ7 Lumix 7.2 MP
Editing: Edited in PhotoShop 7.0 for color accuracy, size, and to apply copyright and border.

Location: Photograph taken at the 2008 Southeastern Michigan Gem and Mineral Show at the Southgate Civic Center in Southgate, Michigan. Show hosted by the Midwest Mineralogical & Lapidary Society.

Description: One large display case at the show held nothing but very large pieces and slices of septarian nodules. The above septarian nodule slice was very large - more than 12 inches in width. It contained a beautiful yellow core of calcite crystals which became progressively darker and deeper in color towards the center. Unfortunately, there was no location information in the display case stating where it was discovered.

This piece when originally found was spherical in shape and that's typical for these types of specimens. It was then cut into slices and each slice was polished to show the beautiful calcite core as well as the internal portions of the randomly fractured/re-healed cement shell. The cement started off as mud probably at the bottom of a sea. Over millions of years and under pressure, the mud gradually dehydrated and chemically changed into a much harder, more durable natural cement.

I'm of the opinion that septarian nodules are one of the most beautiful types of concretions and that they make for some of the most interesting specimens. To me they appear to look like an internal calcite explosion that has been frozen in time.

About Septarian Formation Theories: A number of mechanisms have been proposed by various geologists to try and explain how precisely the septaria (cracks) in septarian nodules formed. One involves the dehydration of clay-rich, gel-rich, or organic-rich cores. Another involves the shrinkage of the concretion's center. A third details the expansion of gases produced by the decay of organic matter within the concretion. Still another describes the brittle fracturing or shrinkage of the concretion interior by either earthquakes or compaction. At this time it is uncertain which, if any, of these and other proposed mechanisms is responsible for the formation of septaria in septarian concretions.

Information Source: [link] (wiki - Septarian Concretions)

Legal: Copyright © Aaron J. Greenblatt. All rights reserved. Commercial use prohibited. This image and commentary may not be used for any reason without expressed written consent.

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Please click here for images of my glass studio located in my other Scraps.
Add a Comment:
KatIsConfused Featured By Owner Dec 31, 2009  Hobbyist General Artist
aww not noodles :(
pretty though
Undistilled Featured By Owner Dec 31, 2009
Thank you. :)

I do have pictures of noodles in this gallery.
UniquelyYours Featured By Owner Dec 31, 2009
I absolutely love this stone. I used it in the necklace I showed you yesterday. [link] It can be shaped into a cab really nice. Has great contrast-
Undistilled Featured By Owner Dec 31, 2009
Agreed, the small ones work really well in jewelry.

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Submitted on
December 30, 2009
Image Size
950 KB


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