sedimentary

Septarian Nodule (Dragon Stone)

Septarian concretion (primarily Calcite, Aragonite, and Limestone/Claystone mixture)

AI-generated identification · may be incorrect

Hardness: 3.5-4; Color: Yellow (calcite), brown (aragonite), and grey (limestone); Luster: Waxy to vitreous; Crystal structure: Trigonal (calcite/aragonite centers); Specific gravity: ~2.60-2.70.

Hardness: 3
Color: Yellow (calcite), brown (aragonite), and grey (limestone)
Luster: Waxy to vitreous

Identified June 26, 2026More sedimentary →

Explore Septarian Nodule (Dragon Stone) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3.5-4; Color: Yellow (calcite), brown (aragonite), and grey (limestone); Luster: Waxy to vitreous; Crystal structure: Trigonal (calcite/aragonite centers); Specific gravity: ~2.60-2.70.

Formation & geological history

Formed during the Cretaceous period (50-70 million years ago) through the desiccation and shrinkage of clay nodules in sea beds, followed by the cracking and subsequent filling of cracks with minerals like calcite and aragonite.

Uses & applications

Primarily used for decorative purposes, ornamental carvings, polished spheres, metaphysical practices (grounding), and as collector specimens.

Geological facts

The name comes from the Latin word 'septum', referring to the partitions or cracks within the stone. They are often called 'Dragon Stones' due to their scaly, cracked appearance that resembles mythical dragon skin.

Field identification & locations

Identify in the field by looking for rounded, dull-looking nodules in sedimentary layers; once cracked or cut, they reveal a unique angular 'star' pattern of veins. Common locations include Utah, USA, and Madagascar.