sedimentary
Septarian Nodule
Septarian Concretion
AI-generated identification · may be incorrectHardness 3.5 to 4 on the Mohs scale, featuring a distinctive mosaic of brown calcite, grey limestone, and yellow barite. Luster is dull to vitreous with a massive crystal structure.
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Physical properties
Hardness 3.5 to 4 on the Mohs scale, featuring a distinctive mosaic of brown calcite, grey limestone, and yellow barite. Luster is dull to vitreous with a massive crystal structure.
Formation & geological history
Formed during the Cretaceous period roughly 50 to 100 million years ago when mud-rich sediments accumulated and cracked as they dried or shrank, allowing mineral-rich waters to precipitate veins inside.
Uses & applications
Popular in ornamental carvings, lapidary arts, and as highly prized decorative display specimens for mineral collectors.
Geological facts
Septarian nodules are often called dragon stones due to their reptilian pattern of intersecting mineral veins.
Field identification & locations
Easily identified by the prominent network of radial cracks filled with contrasting minerals; commonly found in sedimentary clay deposits, notably in Madagascar and Utah.
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