sedimentary
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, Limestone, and Barite)
AI-generated identification · may be incorrectHardness varies from 3 to 4 on the Mohs scale. Colors include brown, yellow, and grey, featuring a dull to vitreous luster and distinct calcified fracture patterns.
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Physical properties
Hardness varies from 3 to 4 on the Mohs scale. Colors include brown, yellow, and grey, featuring a dull to vitreous luster and distinct calcified fracture patterns.
Formation & geological history
Formed in sedimentary mudstone layers during the Cretaceous period, roughly 50 to 100 million years ago, through the shrinkage and mineral infilling of mud balls.
Uses & applications
Used primarily in lapidary arts, decorative carvings, home decor, and as a popular specimen for mineral collectors.
Geological facts
The distinctive spider-web pattern is created by shrinkage cracks that later fill with minerals like yellow calcite.
Field identification & locations
Easily identified by its turtle-shell-like pattern of radial cracks filled with contrasting minerals; commonly found in marine sedimentary deposits worldwide.
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