Rock Identifier
Septarian Nodule (Septarian Concretion (Calcite, Aragonite, Limestone)) — sedimentary
sedimentary

Septarian Nodule

Septarian Concretion (Calcite, Aragonite, Limestone)

AI-generated identification · may be incorrect

Hardness of 3-4 on the Mohs scale. Displays brown, yellow, and grey colors with distinct white or yellow calcite vein networks. Earthy to vitreous luster with a massive, concretionary structure.

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Physical properties

Hardness of 3-4 on the Mohs scale. Displays brown, yellow, and grey colors with distinct white or yellow calcite vein networks. Earthy to vitreous luster with a massive, concretionary structure.

Formation & geological history

Formed in sedimentary muds approximately 50 to 150 million years ago through the dehydration and cracking of concretions, which were later filled with mineral-rich waters.

Uses & applications

Primarily used for decorative items, bookends, cabochons, and as a popular collector specimen.

Geological facts

The name originates from the Latin word septum, meaning partition, due to the radiating pattern of cracks inside the stone.

Field identification & locations

Easily identified by its turtle-shell-like pattern of contrasting mineral veins. Commonly sourced from Madagascar and Utah.

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fossil
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