sedimentary
Yellow Septarian (Dragon Stone)
Septarian Concretion (Calcite, Aragonite, and Limestone)
Hardness: 3.5-4.0 (Mohs); Color: Yellow (Calcite), Brown (Aragonite), Grey (Limestone/Shale); Luster: Vitreous to dull; Crystal Structure: Trigonal/Orthorhombic; Specific Gravity: 2.6-2.8
- Hardness
- 3
- Color
- Yellow (Calcite), Brown (Aragonite), Grey (Limestone/Shale)
- Luster
- Vitreous to dull
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Physical properties
Hardness: 3.5-4.0 (Mohs); Color: Yellow (Calcite), Brown (Aragonite), Grey (Limestone/Shale); Luster: Vitreous to dull; Crystal Structure: Trigonal/Orthorhombic; Specific Gravity: 2.6-2.8
Formation & geological history
Formed as concretions in sea beds during the Cretaceous period (50-70 million years ago). Shrinking mud cracks were later filled with calcite and aragonite crystals.
Uses & applications
Primarily used for lapidary work, ornamental spheres, home decor, and collection. Highly valued in metaphysical communities.
Geological facts
Septarian comes from the Latin word 'septum' meaning wall, referring to the cracks that divide the concretion. Each specimen is unique due to the random nature of the internal cracking.
Field identification & locations
Identified by its distinctive 'turtle skin' or 'mosaic' pattern of yellow calcite and brown aragonite veins against a grey backround. Large deposits are found in Utah and Madagascar.
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