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6" X 5 1/2" X 3" Deep
4.8 lbs
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This may be a
grain of sediment or even a fossil. After formation of the concretion,
the cracks, known as septa, may develop during shrinkage. As is the case
with these specimens, the center of the concretion has shrank to form a
cavity which is lined with a yellowish calcite crystals. Utah
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M422 -
Septarian Concretion Half, Utah
Septarian concretions (Nodules) are often formed of the same material
as the host sidement, but are cemented (concreted) together by silica,
carbonate minerals, or iron oxides. Septarian Concretions are formed by
the segregation of minerals during diagenesis; that is, all the processes
that turn soft, muddy material into rock, and their concentration around
a nucleus.
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