sedimentary

Septarian Nodule (Dragon Stone)

Septarian Concretion (Calcite, Aragonite, and Limestone/Clay)

AI-generated identification · may be incorrect

Hardness: 3.5 to 4.0; Color: Yellow (Calcite), Brown (Aragonite), Gray (Limestone shell); Luster: Waxy to dull (matrix), vitreous (crystals); Crystal structure: Trigonal/Orthorhombic mix inside sedimentary nodules.

Hardness: 3
Color: Yellow (Calcite), Brown (Aragonite), Gray (Limestone shell)
Luster: Waxy to dull (matrix), vitreous (crystals)

Identified July 4, 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

Formation & geological history

Formed during the Cretaceous period, approximately 50 to 70 million years ago. These nodules were formed as sedimentary balls of clay that cracked upon drying; the cracks later filled with mineralized calcite and aragonite.

Uses & applications

Used primarily in jewelry as beads or cabochons, and as ornamental display pieces (bookends, spheres, or polished slabs). Popular in the metaphysical community.

Geological facts

Also known as 'Dragon Stones' due to their scaly, cracked appearance which resembles dragon skin. Most of the high-quality specimens seen today were found in Utah or Madagascar.

Field identification & locations

Identify by the unique 'lightning bolt' or 'cracked porcelain' patterns of yellow and brown against a gray or tan background. Often found along coastal areas where ancient sea levels have recessed.