sedimentary
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, and Limestone)
AI-generated identification · may be incorrectHardness of 3-4 on the Mohs scale. Features a distinctive pattern of angular cavities or cracks filled with yellow calcite and grey limestone.
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Physical properties
Hardness of 3-4 on the Mohs scale. Features a distinctive pattern of angular cavities or cracks filled with yellow calcite and grey limestone.
Formation & geological history
Formed in marine sediments during the Cretaceous period, roughly 50 to 100 million years ago, through the dehydration and cracking of mud-balls.
Uses & applications
Commonly used in lapidary arts, polished display specimens, spheres, and jewelry making due to its striking patterned appearance.
Geological facts
The word septarian derives from the Latin septem, meaning seven, referring to the cracks that typically form in seven-pointed radial patterns.
Field identification & locations
Easily identified by its turtle-shell-like exterior crust and contrasting internal yellow-and-grey crystal veins. Found worldwide, notably in Madagascar and Utah.
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