sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Deep brownish-red; Luster: Dull to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.5-2.9
- Hardness
- 6
- Color
- Deep brownish-red
- Luster
- Dull to waxy
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Deep brownish-red; Luster: Dull to waxy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.5-2.9
Formation & geological history
Jasper is an opaque variety of chalcedony. It forms when silica-rich fluids permeate sedimentary or volcanic rocks, often replacing the original material. The red color is caused by the presence of hematite or other iron oxides during formation.
Uses & applications
Commonly used in jewelry, as tumbled stones, decorative ornaments, and for lapidary work. Historically used for making tools and seals.
Geological facts
Red Jasper is known as the 'Stone of Endurance' and has been used since antiquity for its supposed protective qualities. It was a favorite gemstone in the ancient Mediterranean world.
Field identification & locations
Identified in the field by its opacity (even on thin edges), its deep red color, and its smoothness when water-worn. Common in riverbeds and coastal areas globally.
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