sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull or vitreous; Crystal Structure: Microcrystalline quartz; Cleavage: None; Opaque.
- Hardness
- 6
- Color
- Brick red to brownish-red
- Luster
- Dull or vitreous
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Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Brick red to brownish-red; Luster: Dull or vitreous; Crystal Structure: Microcrystalline quartz; Cleavage: None; Opaque.
Formation & geological history
Jasper is typically formed from the deposition of silica in hydrothermal veins or as part of sedimentary processes where volcanic ash or fine silica-rich sediment is cemented. The red color is caused by the inclusion of iron oxides.
Uses & applications
Popular for use in lapidary arts, jewelry (cabochons and beads), ornamental carvings, and historical use for seals or amulets.
Geological facts
Red jasper was traditionally known as the 'stone of endurance' and was used by ancient civilizations for protective amulets. It is found in massive forms rather than distinct crystals.
Field identification & locations
Identify by its deep red color, hardness (it will scratch glass), and its lack of transparency. Common in areas with quartz veins or sedimentary basins. Look for a conchoidal (shell-like) fracture pattern when broken.
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