Septarian Nodule (Septarian Jasper/Dragon Stone)
Calcite in Aragonite and Limestone concretion · Decorative Stone and Mineral Specimen
Crystal System
Trigonal (Calcite) and Orthorhombic (Aragonite)
Mineral Group
Carbonates
Chemical Formula
CaCO3 (with varying amounts of clay, barite, and iron oxides)
Formation Process
Sedimentary formation through the creation of concretionary nodules in ancient seabeds, followed by shrinking, cracking, and mineral precipitation (calcite/aragonite) into the cavities.
About This Crystal
An oval tumbled and polished specimen featuring distinct patterns of dark brown/grey mudstone separated by yellowish-cream colored calcite veins, creating an eye-like or abstract landscape appearance with a vitreous to waxy luster.
Physical Characteristics
Colors include yellow, brown, grey, and black; white streak; no true cleavage due to massive aggregate nature; conchoidal to uneven fracture; specific gravity around 2.6 - 2.7; brittle tenacity; non-magnetic.
Optical Properties
Uniaxial negative for calcite components with strong birefringence and sometimes fluorescence under UV light, though largely opaque in this polished form.
Hardness & Durability
Origin Region
Madagascar, Utah (USA), New Zealand, England
Hardness & Durability
Mohs hardness varies by mineral phase: 3.5 to 4 for the calcite veins and 3.5 for the aragonite/limestone matrix. Moderate durability; sensitive to acids due to carbonate content.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid acidic cleaners, vinegar, lemon juice, ultrasonic cleaners, and prolonged exposure to harsh chemicals or direct sunlight.
Rarity & Value
Common to uncommon; value depends on the intricacy of the pattern, polish quality, and size, ranging from affordable tumbled stones to expensive large display nodules.
Special Characteristics
Distinctive septarian crack patterns filled with secondary minerals, sometimes exhibiting fluorescence under ultraviolet light.
Lore & History
Often referred to as 'Dragon Stone' due to its dragon-scale appearance. In crystal healing lore, it is associated with the root chakra, grounding, promoting patience, and enhancing communication abilities, though these are traditional beliefs rather than scientific claims.