sedimentary
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, and Limestone)
AI-generated identification · may be incorrectHardness of 3.5 to 4 on the Mohs scale with a dull to vitreous luster. Features a distinctive pattern of angular cavities filled with yellow calcite and brown aragonite.
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Physical properties
Hardness of 3.5 to 4 on the Mohs scale with a dull to vitreous luster. Features a distinctive pattern of angular cavities filled with yellow calcite and brown aragonite.
Formation & geological history
Formed roughly 50 to 70 million years ago during the Cretaceous period through the drying and cracking of mud-balls in ancient seabeds.
Uses & applications
Popularly used for decorative carvings, ornamental egg shapes, and sought after by mineral collectors.
Geological facts
The name originates from the Latin word 'septum', meaning partition, referring to the radiating cracks inside the concretion.
Field identification & locations
Easily identified by its turtle-back surface pattern and contrasting mineral fillings, commonly sourced from Madagascar and the USA.
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