sedimentary

Dragon Stone (Septarian Nodule/Concretion)

Septarian Concretion (Composition: Calcite, Aragonite, Limestone/Clay)

Hardness: 3.5-4 (Mohs scale); Color: Brown, tan, yellow, and grey; Luster: Earthy to vitreous; Crystal structure: Trigonal/Orthorhombic; Cleavage: Perfect rhombohedral in calcite areas; Specific gravity: 2.7

Hardness: 3
Color: Brown, tan, yellow, and grey
Luster: Earthy to vitreous

Identified March 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed during the Cretaceous period (approx. 50-70 million years ago). They originated as mud balls on ancient seabed floors that cracked due to dehydration and mineralized as calcite and aragonite filled the interior voids.

Uses & applications

Primarily used as decorative display pieces, lapidary carvings (spheres, eggs), jewelry (mostly cabochons), and as a popular focus for metaphysical collectors.

Geological facts

The name 'Septarian' comes from the Latin word 'septum' meaning partition; the patterns represent the shrinking and cracking of prehistoric clay. They are often nicknamed 'Dragon Stones' because the geometric patterns resemble dragon skin.

Field identification & locations

Identify by looking for 'leathery' or cracked exterior textures with internal crystalline veins. They are most famously found in abundance in Southern Utah (USA) and Madagascar. To find them, look for rounded nodules in dry creek beds or clay-rich exposures.

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