sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs), Color: Opaque brick red to deep brownish-red with white quartz veins, Luster: Dull to vitreous when polished, Crystal Structure: Trigonal/Microcrystalline (cryptocrystalline), Cleavage: None/Conchoidal fracture
- Hardness
- 6
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Physical properties
Hardness: 6.5-7 (Mohs), Color: Opaque brick red to deep brownish-red with white quartz veins, Luster: Dull to vitreous when polished, Crystal Structure: Trigonal/Microcrystalline (cryptocrystalline), Cleavage: None/Conchoidal fracture
Formation & geological history
Formed when fine silica-rich sediments or volcanic ash are consolidated through the action of hydrothermal fluids. The red color is caused by high concentrations of iron oxide (hematite) inclusions within the quartz matrix. Found in ancient sedimentary and metamorphic sequences globally.
Uses & applications
Commonly used as a gemstone for jewelry (cabochons, beads), decorative carvings, pocket stones, and architectural ornamentation. Historically used for making tools and seals.
Geological facts
Red Jasper has been used since ancient times in jewelry and amulets, often associated with vitality and strength. It is a common component of 'banded iron formations' which provide some of the world's most important iron ore deposits.
Field identification & locations
Identify by its characteristic opaque earthy red color and white or black banding. It will scratch glass but cannot be scratched by a steel knife. Common locations include South Africa, India, Brazil, and the Southwestern United States.
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